Interface Map<K,​V>

  • Type Parameters:
    K - Key type
    V - Value type
    All Superinterfaces:
    Foldable<Tuple2<K,​V>>, java.util.function.Function<K,​V>, Function1<K,​V>, java.lang.Iterable<Tuple2<K,​V>>, PartialFunction<K,​V>, java.io.Serializable, Traversable<Tuple2<K,​V>>, Value<Tuple2<K,​V>>
    All Known Subinterfaces:
    SortedMap<K,​V>
    All Known Implementing Classes:
    HashMap, LinkedHashMap, TreeMap

    public interface Map<K,​V>
    extends Traversable<Tuple2<K,​V>>, PartialFunction<K,​V>, java.io.Serializable
    An immutable Map interface.

    Represents a collection of key-value pairs with immutable operations. Supports typical map operations such as querying, updating, filtering, transforming, and iterating over entries. Provides convenient methods for converting to standard Java maps and for working with default values.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static long serialVersionUID
      The serial version UID for serialization.
    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Default Methods Deprecated Methods 
      Modifier and Type Method Description
      default V apply​(K key)
      Deprecated.
      default PartialFunction<K,​V> asPartialFunction()
      Turns this Map into a PartialFunction which is defined at a specific index, if this Map contains the given key.
      <K2,​V2>
      Map<K2,​V2>
      bimap​(@NonNull java.util.function.Function<? super K,​? extends K2> keyMapper, @NonNull java.util.function.Function<? super V,​? extends V2> valueMapper)
      Maps this Map to a new Map with different component type by applying a function to its elements.
      default <R> Seq<R> collect​(@NonNull PartialFunction<? super Tuple2<K,​V>,​? extends R> partialFunction)
      Applies a PartialFunction to all elements that are defined for it and collects the results.
      Tuple2<V,​? extends Map<K,​V>> computeIfAbsent​(K key, @NonNull java.util.function.Function<? super K,​? extends V> mappingFunction)
      If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map.
      Tuple2<Option<V>,​? extends Map<K,​V>> computeIfPresent​(K key, @NonNull java.util.function.BiFunction<? super K,​? super V,​? extends V> remappingFunction)
      If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
      default boolean contains​(@NonNull Tuple2<K,​V> element)
      Shortcut for exists(e -> Objects.equals(e, element)), tests if the given element is contained.
      boolean containsKey​(K key)
      Returns true if this map contains a mapping for the specified key.
      default boolean containsValue​(V value)
      Returns true if this map maps one or more keys to the specified value.
      Map<K,​V> distinct()
      Returns a new Traversable containing the elements of this instance with all duplicates removed.
      Map<K,​V> distinctBy​(@NonNull java.util.Comparator<? super Tuple2<K,​V>> comparator)
      Returns a new Traversable containing the elements of this instance without duplicates, as determined by the given comparator.
      <U> Map<K,​V> distinctBy​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends U> keyExtractor)
      Returns a new Traversable containing the elements of this instance without duplicates, based on keys extracted from elements using keyExtractor.
      Map<K,​V> drop​(int n)
      Returns a new Traversable without the first n elements, or an empty instance if this contains fewer than n elements.
      Map<K,​V> dropRight​(int n)
      Returns a new Traversable without the last n elements, or an empty instance if this contains fewer than n elements.
      Map<K,​V> dropUntil​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Returns a new Traversable starting from the first element that satisfies the given predicate, dropping all preceding elements.
      Map<K,​V> dropWhile​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Returns a new Traversable starting from the first element that does not satisfy the given predicate, dropping all preceding elements.
      static <K,​V>
      Tuple2<K,​V>
      entry​(K key, V value)
      Creates a key/value pair for use with Map factories.
      Map<K,​V> filter​(@NonNull java.util.function.BiPredicate<? super K,​? super V> predicate)
      Returns a new Map consisting of all elements which satisfy the given predicate.
      Map<K,​V> filter​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Returns a new traversable containing only the elements that satisfy the given predicate.
      Map<K,​V> filterKeys​(@NonNull java.util.function.Predicate<? super K> predicate)
      Returns a new Map consisting of all elements with keys which satisfy the given predicate.
      Map<K,​V> filterValues​(@NonNull java.util.function.Predicate<? super V> predicate)
      Returns a new Map consisting of all elements with values which satisfy the given predicate.
      <K2,​V2>
      Map<K2,​V2>
      flatMap​(@NonNull java.util.function.BiFunction<? super K,​? super V,​? extends java.lang.Iterable<Tuple2<K2,​V2>>> mapper)
      FlatMaps this Map to a new Map with different component type.
      default <U> Seq<U> flatMap​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends java.lang.Iterable<? extends U>> mapper)
      Flat-maps this entries to a sequence of values.
      default <U> U foldRight​(U zero, @NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super U,​? extends U> f)
      Folds the elements of this structure from the right, starting with the given zero value and successively applying the combine function to each element.
      default void forEach​(@NonNull java.util.function.BiConsumer<K,​V> action)
      Performs an action on key, value pair.
      Option<V> get​(K key)
      Returns the Some of value to which the specified key is mapped, or None if this map contains no mapping for the key.
      V getOrElse​(K key, V defaultValue)
      Returns the value associated with a key, or a default value if the key is not contained in the map.
      <C> Map<C,​? extends Map<K,​V>> groupBy​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends C> classifier)
      Groups elements of this Traversable based on a classifier function.
      Iterator<? extends Map<K,​V>> grouped​(int size)
      Splits this Traversable into consecutive blocks of the given size.
      default boolean hasDefiniteSize()
      Indicates whether this Traversable has a known finite size.
      Map<K,​V> init()
      Returns all elements of this Traversable except the last one.
      Option<? extends Map<K,​V>> initOption()
      Returns all elements of this Traversable except the last one, wrapped in an Option.
      default boolean isDefinedAt​(K key)
      Deprecated.
      default boolean isDistinct()
      Indicates whether this Traversable may contain only distinct elements.
      default boolean isTraversableAgain()
      Checks if this Traversable can be traversed multiple times without side effects.
      @NonNull Iterator<Tuple2<K,​V>> iterator()
      Returns an iterator over the elements of this Traversable, implemented via Traversable.head() and Traversable.tail().
      default <U> Iterator<U> iterator​(@NonNull java.util.function.BiFunction<K,​V,​? extends U> mapper)
      Iterates this Map sequentially, mapping the (key, value) pairs to elements.
      Set<K> keySet()
      Returns the keys contained in this map.
      default Iterator<K> keysIterator()
      Returns the keys contained in this map as an iterator.
      default int length()
      Returns the number of elements in this Traversable.
      default Function1<K,​Option<V>> lift()
      Turns this map into a plain function returning an Option result.
      <K2,​V2>
      Map<K2,​V2>
      map​(@NonNull java.util.function.BiFunction<? super K,​? super V,​Tuple2<K2,​V2>> mapper)
      Maps the entries of this Map to form a new Map.
      default <U> Seq<U> map​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends U> mapper)
      Maps the Map entries to a sequence of values.
      <K2> Map<K2,​V> mapKeys​(@NonNull java.util.function.Function<? super K,​? extends K2> keyMapper)
      Maps the keys of this Map while preserving the corresponding values.
      <K2> Map<K2,​V> mapKeys​(@NonNull java.util.function.Function<? super K,​? extends K2> keyMapper, @NonNull java.util.function.BiFunction<? super V,​? super V,​? extends V> valueMerge)
      Maps the keys of this Map while preserving the corresponding values and applying a value merge function on collisions.
      default <U> Seq<U> mapTo​(U value)
      Maps the underlying value to another fixed value.
      default Seq<java.lang.Void> mapToVoid()
      Maps the underlying value to Void
      <V2> Map<K,​V2> mapValues​(@NonNull java.util.function.Function<? super V,​? extends V2> valueMapper)
      Maps the values of this Map while preserving the corresponding keys.
      Map<K,​V> merge​(@NonNull Map<? extends K,​? extends V> that)
      Creates a new map which by merging the entries of this map and that map.
      <U extends V>
      Map<K,​V>
      merge​(@NonNull Map<? extends K,​U> that, @NonNull java.util.function.BiFunction<? super V,​? super U,​? extends V> collisionResolution)
      Creates a new map which by merging the entries of this map and that map.
      static <K,​V>
      Map<K,​V>
      narrow​(Map<? extends K,​? extends V> map)
      Narrows a widened Map<? extends K, ? extends V> to Map<K, V> by performing a type-safe cast.
      Map<K,​V> orElse​(@NonNull java.util.function.Supplier<? extends java.lang.Iterable<? extends Tuple2<K,​V>>> supplier)
      Returns this Traversable if it is non-empty; otherwise, returns the result of evaluating the given supplier.
      Map<K,​V> orElse​(java.lang.Iterable<? extends Tuple2<K,​V>> other)
      Returns this Traversable if it is non-empty; otherwise, returns the given alternative.
      Tuple2<? extends Map<K,​V>,​? extends Map<K,​V>> partition​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Splits this Traversable into two partitions according to a predicate.
      Map<K,​V> peek​(@NonNull java.util.function.Consumer<? super Tuple2<K,​V>> action)
      Performs the given action on the first element if this is an eager implementation.
      Map<K,​V> put​(@NonNull Tuple2<? extends K,​? extends V> entry)
      Convenience method for put(entry._1, entry._2).
      <U extends V>
      Map<K,​V>
      put​(@NonNull Tuple2<? extends K,​U> entry, @NonNull java.util.function.BiFunction<? super V,​? super U,​? extends V> merge)
      Convenience method for put(entry._1, entry._2, merge).
      <U extends V>
      Map<K,​V>
      put​(K key, U value, @NonNull java.util.function.BiFunction<? super V,​? super U,​? extends V> merge)
      Associates the specified value with the specified key in this map.
      Map<K,​V> put​(K key, V value)
      Associates the specified value with the specified key in this map.
      Map<K,​V> reject​(@NonNull java.util.function.BiPredicate<? super K,​? super V> predicate)
      Returns a new Map consisting of all elements which do not satisfy the given predicate.
      Map<K,​V> reject​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Returns a new traversable containing only the elements that do not satisfy the given predicate.
      Map<K,​V> rejectKeys​(@NonNull java.util.function.Predicate<? super K> predicate)
      Returns a new Map consisting of all elements with keys which do not satisfy the given predicate.
      Map<K,​V> rejectValues​(@NonNull java.util.function.Predicate<? super V> predicate)
      Returns a new Map consisting of all elements with values which do not satisfy the given predicate.
      Map<K,​V> remove​(K key)
      Removes the mapping for a key from this map if it is present.
      Map<K,​V> removeAll​(@NonNull java.lang.Iterable<? extends K> keys)
      Removes the mapping for a key from this map if it is present.
      Map<K,​V> removeAll​(@NonNull java.util.function.BiPredicate<? super K,​? super V> predicate)
      Deprecated.
      Map<K,​V> removeKeys​(@NonNull java.util.function.Predicate<? super K> predicate)
      Deprecated.
      Map<K,​V> removeValues​(@NonNull java.util.function.Predicate<? super V> predicate)
      Deprecated.
      Map<K,​V> replace​(@NonNull Tuple2<K,​V> currentElement, @NonNull Tuple2<K,​V> newElement)
      Replaces the first occurrence of currentElement with newElement, if it exists.
      Map<K,​V> replace​(K key, V oldValue, V newValue)
      Replaces the entry for the specified key only if currently mapped to the specified value.
      Map<K,​V> replaceAll​(@NonNull Tuple2<K,​V> currentElement, Tuple2<K,​V> newElement)
      Replaces all occurrences of currentElement with newElement.
      Map<K,​V> replaceAll​(@NonNull java.util.function.BiFunction<? super K,​? super V,​? extends V> function)
      Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception.
      Map<K,​V> replaceValue​(K key, V value)
      Replaces the entry for the specified key only if it is currently mapped to some value.
      Map<K,​V> retainAll​(@NonNull java.lang.Iterable<? extends Tuple2<K,​V>> elements)
      Retains only the elements from this Traversable that are contained in the given elements.
      Map<K,​V> scan​(@NonNull Tuple2<K,​V> zero, @NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super Tuple2<K,​V>,​? extends Tuple2<K,​V>> operation)
      Computes a prefix scan of the elements of this Traversable.
      default <U> Seq<U> scanLeft​(U zero, @NonNull java.util.function.BiFunction<? super U,​? super Tuple2<K,​V>,​? extends U> operation)
      Produces a collection containing cumulative results of applying the operator from left to right.
      default <U> Seq<U> scanRight​(U zero, @NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super U,​? extends U> operation)
      Produces a collection containing cumulative results of applying the operator from right to left.
      int size()
      Returns the number of elements in this Traversable.
      Iterator<? extends Map<K,​V>> slideBy​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​?> classifier)
      Partitions this Traversable into consecutive non-overlapping windows according to a classification function.
      Iterator<? extends Map<K,​V>> sliding​(int size)
      Slides a window of a given size over this Traversable with a step size of 1.
      Iterator<? extends Map<K,​V>> sliding​(int size, int step)
      Slides a window of a specific size with a given step over this Traversable.
      Tuple2<? extends Map<K,​V>,​? extends Map<K,​V>> span​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Splits this Traversable into a prefix and remainder according to the given predicate.
      Map<K,​V> tail()
      Returns a new Traversable without its first element.
      Option<? extends Map<K,​V>> tailOption()
      Returns a new Traversable without its first element as an Option.
      Map<K,​V> take​(int n)
      Returns the first n elements of this Traversable, or all elements if n exceeds the length.
      Map<K,​V> takeRight​(int n)
      Returns the last n elements of this Traversable, or all elements if n exceeds the length.
      Map<K,​V> takeUntil​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Takes elements from this Traversable until the given predicate holds for an element.
      Map<K,​V> takeWhile​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
      Takes elements from this Traversable while the given predicate holds.
      java.util.Map<K,​V> toJavaMap()
      Converts this Vavr Map to a java.util.Map while preserving characteristics like insertion order (LinkedHashMap) and sort order (SortedMap).
      default <U> U transform​(@NonNull java.util.function.Function<? super Map<K,​V>,​? extends U> f)
      Transforms this Map.
      default Tuple2<Seq<K>,​Seq<V>> unzip()
      Unzips the entries of this Map by treating each key-value pair as an element, and splitting them into two separate Seq collections - one for keys and one for values.
      default <T1,​T2>
      Tuple2<Seq<T1>,​Seq<T2>>
      unzip​(@NonNull java.util.function.BiFunction<? super K,​? super V,​Tuple2<? extends T1,​? extends T2>> unzipper)
      Unzips the entries of this Map by mapping each key-value pair to a tuple.
      default <T1,​T2>
      Tuple2<Seq<T1>,​Seq<T2>>
      unzip​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​Tuple2<? extends T1,​? extends T2>> unzipper)
      Unzips the elements of this Traversable by mapping each element to a pair and splitting them into two separate Traversable collections.
      default <T1,​T2,​T3>
      Tuple3<Seq<T1>,​Seq<T2>,​Seq<T3>>
      unzip3​(@NonNull java.util.function.BiFunction<? super K,​? super V,​Tuple3<? extends T1,​? extends T2,​? extends T3>> unzipper)
      Unzips the entries of this Map by mapping each key-value pair to a triple.
      default <T1,​T2,​T3>
      Tuple3<Seq<T1>,​Seq<T2>,​Seq<T3>>
      unzip3​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​Tuple3<? extends T1,​? extends T2,​? extends T3>> unzipper)
      Unzips the elements of this Traversable by mapping each element to a triple and splitting them into three separate Traversable collections.
      Seq<V> values()
      Returns a new Seq that contains the values of this Map.
      default Iterator<V> valuesIterator()
      Returns the values in this map.
      default Function1<K,​V> withDefault​(@NonNull java.util.function.Function<? super K,​? extends V> defaultFunction)
      Deprecated.
      Will be removed
      default Function1<K,​V> withDefaultValue​(V defaultValue)
      Deprecated.
      Will be removed
      default <U> Seq<Tuple2<Tuple2<K,​V>,​U>> zip​(@NonNull java.lang.Iterable<? extends U> that)
      Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable.
      default <U> Seq<Tuple2<Tuple2<K,​V>,​U>> zipAll​(@NonNull java.lang.Iterable<? extends U> that, Tuple2<K,​V> thisElem, U thatElem)
      Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable, filling in placeholder elements when one collection is shorter than the other.
      default <U,​R>
      Seq<R>
      zipWith​(@NonNull java.lang.Iterable<? extends U> that, java.util.function.BiFunction<? super Tuple2<K,​V>,​? super U,​? extends R> mapper)
      Returns a Traversable by combining elements of this Traversable with elements of another Iterable using a mapping function.
      default Seq<Tuple2<Tuple2<K,​V>,​java.lang.Integer>> zipWithIndex()
      Zips this Traversable with its indices, starting at 0.
      default <U> Seq<U> zipWithIndex​(@NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super java.lang.Integer,​? extends U> mapper)
      Zips this Traversable with its indices and maps the resulting pairs using the provided mapper.
    • Field Detail

      • serialVersionUID

        static final long serialVersionUID
        The serial version UID for serialization.
        See Also:
        Constant Field Values
    • Method Detail

      • narrow

        static <K,​V> Map<K,​V> narrow​(Map<? extends K,​? extends V> map)
        Narrows a widened Map<? extends K, ? extends V> to Map<K, V> by performing a type-safe cast. This is eligible because immutable/read-only collections are covariant.
        Type Parameters:
        K - Key type
        V - Value type
        Parameters:
        map - A Map.
        Returns:
        the given map instance as narrowed type Map<K, V>.
      • entry

        static <K,​V> Tuple2<K,​V> entry​(K key,
                                                   V value)
        Creates a key/value pair for use with Map factories.

        When imported statically, this method enables constructing maps in a readable and type-safe way, for example:

        
         HashMap.ofEntries(
             entry(k1, v1),
             entry(k2, v2),
             entry(k3, v3)
         );
         
        Type Parameters:
        K - key type
        V - value type
        Parameters:
        key - the entry's key
        value - the entry's value
        Returns:
        a key/value pair
      • apply

        @Deprecated
        default V apply​(K key)
        Deprecated.
        Description copied from interface: PartialFunction
        Applies this function to the given argument and returns the result.
        Specified by:
        apply in interface java.util.function.Function<K,​V>
        Specified by:
        apply in interface Function1<K,​V>
        Specified by:
        apply in interface PartialFunction<K,​V>
        Parameters:
        key - the input argument
        Returns:
        the result of applying this function to the input
      • asPartialFunction

        default PartialFunction<K,​V> asPartialFunction()
                                                      throws java.util.NoSuchElementException
        Turns this Map into a PartialFunction which is defined at a specific index, if this Map contains the given key. When applied to a defined key, the partial function will return the value of this Map that is associated with the key.
        Returns:
        a new PartialFunction
        Throws:
        java.util.NoSuchElementException - when a non-existing key is applied to the partial function
      • collect

        default <R> Seq<R> collect​(@NonNull PartialFunction<? super Tuple2<K,​V>,​? extends R> partialFunction)
        Description copied from interface: Traversable
        Applies a PartialFunction to all elements that are defined for it and collects the results.

        For each element in iteration order, the function is first tested:

        
         partialFunction.isDefinedAt(element)
         
        If true, the element is mapped to type R:
        
         R newElement = partialFunction.apply(element)
         

        Note: If this Traversable is ordered (i.e., extends Ordered), the caller must ensure that the resulting elements are comparable (i.e., implement Comparable).

        Specified by:
        collect in interface Traversable<K>
        Type Parameters:
        R - the type of elements in the resulting Traversable
        Parameters:
        partialFunction - a function that may not be defined for all elements of this traversable
        Returns:
        a new Traversable containing the results of applying the partial function
      • bimap

        <K2,​V2> Map<K2,​V2> bimap​(@NonNull java.util.function.Function<? super K,​? extends K2> keyMapper,
                                             @NonNull java.util.function.Function<? super V,​? extends V2> valueMapper)
        Maps this Map to a new Map with different component type by applying a function to its elements.
        Type Parameters:
        K2 - key's component type of the map result
        V2 - value's component type of the map result
        Parameters:
        keyMapper - a Function that maps the keys of type K to keys of type K2
        valueMapper - a Function that the values of type V to values of type V2
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if keyMapper or valueMapper is null
      • contains

        default boolean contains​(@NonNull Tuple2<K,​V> element)
        Description copied from interface: Value
        Shortcut for exists(e -> Objects.equals(e, element)), tests if the given element is contained.
        Specified by:
        contains in interface Value<K>
        Parameters:
        element - An Object of type A, may be null.
        Returns:
        true, if element is contained, false otherwise.
      • computeIfAbsent

        Tuple2<V,​? extends Map<K,​V>> computeIfAbsent​(K key,
                                                                 @NonNull java.util.function.Function<? super K,​? extends V> mappingFunction)
        If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map.
        Parameters:
        key - key whose presence in this map is to be tested
        mappingFunction - mapping function
        Returns:
        the Tuple2 of current or modified map and existing or computed value associated with the specified key
      • computeIfPresent

        Tuple2<Option<V>,​? extends Map<K,​V>> computeIfPresent​(K key,
                                                                          @NonNull java.util.function.BiFunction<? super K,​? super V,​? extends V> remappingFunction)
        If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value.
        Parameters:
        key - key whose presence in this map is to be tested
        remappingFunction - remapping function
        Returns:
        the Tuple2 of current or modified map and the Some of the value associated with the specified key, or None if none
      • containsKey

        boolean containsKey​(K key)
        Returns true if this map contains a mapping for the specified key.
        Parameters:
        key - key whose presence in this map is to be tested
        Returns:
        true if this map contains a mapping for the specified key
      • containsValue

        default boolean containsValue​(V value)
        Returns true if this map maps one or more keys to the specified value. This operation will require time linear in the map size.
        Parameters:
        value - value whose presence in this map is to be tested
        Returns:
        true if this map maps one or more keys to the specified value
      • filter

        Map<K,​V> filter​(@NonNull java.util.function.BiPredicate<? super K,​? super V> predicate)
        Returns a new Map consisting of all elements which satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • reject

        Map<K,​V> reject​(@NonNull java.util.function.BiPredicate<? super K,​? super V> predicate)
        Returns a new Map consisting of all elements which do not satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • filterKeys

        Map<K,​V> filterKeys​(@NonNull java.util.function.Predicate<? super K> predicate)
        Returns a new Map consisting of all elements with keys which satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test keys of elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • rejectKeys

        Map<K,​V> rejectKeys​(@NonNull java.util.function.Predicate<? super K> predicate)
        Returns a new Map consisting of all elements with keys which do not satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test keys of elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • filterValues

        Map<K,​V> filterValues​(@NonNull java.util.function.Predicate<? super V> predicate)
        Returns a new Map consisting of all elements with values which satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test values of elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • rejectValues

        Map<K,​V> rejectValues​(@NonNull java.util.function.Predicate<? super V> predicate)
        Returns a new Map consisting of all elements with values which do not satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test values of elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • flatMap

        <K2,​V2> Map<K2,​V2> flatMap​(@NonNull java.util.function.BiFunction<? super K,​? super V,​? extends java.lang.Iterable<Tuple2<K2,​V2>>> mapper)
        FlatMaps this Map to a new Map with different component type.
        Type Parameters:
        K2 - key's component type of the mapped Map
        V2 - value's component type of the mapped Map
        Parameters:
        mapper - A mapper
        Returns:
        A new Map.
        Throws:
        java.lang.NullPointerException - if mapper is null
      • flatMap

        default <U> Seq<U> flatMap​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends java.lang.Iterable<? extends U>> mapper)
        Flat-maps this entries to a sequence of values.

        Please use flatMap(BiFunction) if the result should be a Map

        Specified by:
        flatMap in interface Traversable<K>
        Type Parameters:
        U - Component type
        Parameters:
        mapper - A mapper
        Returns:
        A sequence of flat-mapped values.
      • foldRight

        default <U> U foldRight​(U zero,
                                @NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super U,​? extends U> f)
        Description copied from interface: Foldable
        Folds the elements of this structure from the right, starting with the given zero value and successively applying the combine function to each element.

        Folding from the right means that elements are combined starting from the last element and associating each step with the accumulated result so far.

        Example:

        
         // Result: "!cba"
         List.of("a", "b", "c").foldRight("!", (x, acc) -> acc + x);
         
        Specified by:
        foldRight in interface Foldable<K>
        Specified by:
        foldRight in interface Traversable<K>
        Type Parameters:
        U - the type of the accumulated result
        Parameters:
        zero - the initial value to start folding with
        f - a function that combines the next element and the accumulated value
        Returns:
        the folded result
      • forEach

        default void forEach​(@NonNull java.util.function.BiConsumer<K,​V> action)
        Performs an action on key, value pair.
        Parameters:
        action - A BiConsumer
        Throws:
        java.lang.NullPointerException - if action is null
      • get

        Option<V> get​(K key)
        Returns the Some of value to which the specified key is mapped, or None if this map contains no mapping for the key.
        Parameters:
        key - the key whose associated value is to be returned
        Returns:
        the Some of value to which the specified key is mapped, or None if this map contains no mapping for the key
      • getOrElse

        V getOrElse​(K key,
                    V defaultValue)
        Returns the value associated with a key, or a default value if the key is not contained in the map.
        Parameters:
        key - the key
        defaultValue - a default value
        Returns:
        the value associated with key if it exists, otherwise the default value.
      • hasDefiniteSize

        default boolean hasDefiniteSize()
        Description copied from interface: Traversable
        Indicates whether this Traversable has a known finite size.

        This should typically be implemented by concrete classes, not interfaces.

        Specified by:
        hasDefiniteSize in interface Traversable<K>
        Returns:
        true if the number of elements is finite and known, false otherwise.
      • isTraversableAgain

        default boolean isTraversableAgain()
        Description copied from interface: Traversable
        Checks if this Traversable can be traversed multiple times without side effects.

        Implementations should provide the correct behavior; this is not meant for interfaces alone.

        Specified by:
        isTraversableAgain in interface Traversable<K>
        Returns:
        true if this Traversable is guaranteed to be repeatably traversable, false otherwise
      • iterator

        default <U> Iterator<U> iterator​(@NonNull java.util.function.BiFunction<K,​V,​? extends U> mapper)
        Iterates this Map sequentially, mapping the (key, value) pairs to elements.
        Type Parameters:
        U - The type of the resulting elements
        Parameters:
        mapper - A function that maps (key, value) pairs to elements of type U
        Returns:
        An iterator through the mapped elements.
      • keySet

        Set<K> keySet()
        Returns the keys contained in this map.
        Returns:
        Set of the keys contained in this map.
      • keysIterator

        default Iterator<K> keysIterator()
        Returns the keys contained in this map as an iterator.
        Returns:
        Iterator of the keys contained in this map.
      • length

        default int length()
        Description copied from interface: Traversable
        Returns the number of elements in this Traversable.

        Equivalent to Traversable.size().

        Specified by:
        length in interface Traversable<K>
        Returns:
        the number of elements
      • lift

        default Function1<K,​Option<V>> lift()
        Turns this map into a plain function returning an Option result.
        Specified by:
        lift in interface PartialFunction<K,​V>
        Returns:
        a function that takes a key k and returns its value in a Some if found, otherwise a None.
      • map

        default <U> Seq<U> map​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends U> mapper)
        Maps the Map entries to a sequence of values.

        Please use map(BiFunction) if the result has to be of type Map.

        Specified by:
        map in interface Traversable<K>
        Specified by:
        map in interface Value<K>
        Type Parameters:
        U - Component type
        Parameters:
        mapper - A mapper
        Returns:
        A sequence of mapped values.
      • mapTo

        default <U> Seq<U> mapTo​(U value)
        Description copied from interface: Value
        Maps the underlying value to another fixed value.
        Specified by:
        mapTo in interface Traversable<K>
        Specified by:
        mapTo in interface Value<K>
        Type Parameters:
        U - The new component type
        Parameters:
        value - value to replace the contents with
        Returns:
        A new value
      • mapToVoid

        default Seq<java.lang.Void> mapToVoid()
        Description copied from interface: Value
        Maps the underlying value to Void
        Specified by:
        mapToVoid in interface Traversable<K>
        Specified by:
        mapToVoid in interface Value<K>
        Returns:
        A new value of type Void
      • map

        <K2,​V2> Map<K2,​V2> map​(@NonNull java.util.function.BiFunction<? super K,​? super V,​Tuple2<K2,​V2>> mapper)
        Maps the entries of this Map to form a new Map.
        Type Parameters:
        K2 - key's component type of the map result
        V2 - value's component type of the map result
        Parameters:
        mapper - a Function that maps entries of type (K, V) to entries of type (K2, V2)
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if mapper is null
      • mapKeys

        <K2> Map<K2,​V> mapKeys​(@NonNull java.util.function.Function<? super K,​? extends K2> keyMapper)
        Maps the keys of this Map while preserving the corresponding values.

        The size of the result map may be smaller if keyMapper maps two or more distinct keys to the same new key. In this case the value at the latest of the original keys is retained. Order of keys is predictable in TreeMap (by comparator) and LinkedHashMap (insertion-order) and not predictable in HashMap.

        Type Parameters:
        K2 - the new key type
        Parameters:
        keyMapper - a Function that maps keys of type V to keys of type V2
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if keyMapper is null
      • mapKeys

        <K2> Map<K2,​V> mapKeys​(@NonNull java.util.function.Function<? super K,​? extends K2> keyMapper,
                                     @NonNull java.util.function.BiFunction<? super V,​? super V,​? extends V> valueMerge)
        Maps the keys of this Map while preserving the corresponding values and applying a value merge function on collisions.

        The size of the result map may be smaller if keyMapper maps two or more distinct keys to the same new key. In this case the associated values will be combined using valueMerge.

        Type Parameters:
        K2 - the new key type
        Parameters:
        keyMapper - a Function that maps keys of type V to keys of type V2
        valueMerge - a BiFunction that merges values
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if keyMapper is null
      • mapValues

        <V2> Map<K,​V2> mapValues​(@NonNull java.util.function.Function<? super V,​? extends V2> valueMapper)
        Maps the values of this Map while preserving the corresponding keys.
        Type Parameters:
        V2 - the new value type
        Parameters:
        valueMapper - a Function that maps values of type V to values of type V2
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if valueMapper is null
      • merge

        Map<K,​V> merge​(@NonNull Map<? extends K,​? extends V> that)
        Creates a new map which by merging the entries of this map and that map.

        If collisions occur, the value of this map is taken.

        Parameters:
        that - the other map
        Returns:
        A merged map
        Throws:
        java.lang.NullPointerException - if that map is null
      • merge

        <U extends VMap<K,​V> merge​(@NonNull Map<? extends K,​U> that,
                                           @NonNull java.util.function.BiFunction<? super V,​? super U,​? extends V> collisionResolution)
        Creates a new map which by merging the entries of this map and that map.

        Uses the specified collision resolution function if two keys are the same. The collision resolution function will always take the first argument from this map and the second from that map.

        Type Parameters:
        U - value type of that Map
        Parameters:
        that - the other map
        collisionResolution - the collision resolution function
        Returns:
        A merged map
        Throws:
        java.lang.NullPointerException - if that map or the given collision resolution function is null
      • put

        Map<K,​V> put​(K key,
                           V value)
        Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced by the specified value.
        Parameters:
        key - key with which the specified value is to be associated
        value - value to be associated with the specified key
        Returns:
        A new Map containing these elements and that entry.
      • put

        Map<K,​V> put​(@NonNull Tuple2<? extends K,​? extends V> entry)
        Convenience method for put(entry._1, entry._2).
        Parameters:
        entry - A Tuple2 containing the key and value
        Returns:
        A new Map containing these elements and that entry.
      • put

        <U extends VMap<K,​V> put​(K key,
                                         U value,
                                         @NonNull java.util.function.BiFunction<? super V,​? super U,​? extends V> merge)
        Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the merge function is used to combine the previous value to the value to be inserted, and the result of that call is inserted in the map.
        Type Parameters:
        U - the value type
        Parameters:
        key - key with which the specified value is to be associated
        value - value to be associated with the specified key
        merge - function taking the old and new values and merging them.
        Returns:
        A new Map containing these elements and that entry.
      • put

        <U extends VMap<K,​V> put​(@NonNull Tuple2<? extends K,​U> entry,
                                         @NonNull java.util.function.BiFunction<? super V,​? super U,​? extends V> merge)
        Convenience method for put(entry._1, entry._2, merge).
        Type Parameters:
        U - the value type
        Parameters:
        entry - A Tuple2 containing the key and value
        merge - function taking the old and new values and merging them.
        Returns:
        A new Map containing these elements and that entry.
      • remove

        Map<K,​V> remove​(K key)
        Removes the mapping for a key from this map if it is present.
        Parameters:
        key - key whose mapping is to be removed from the map
        Returns:
        A new Map containing these elements without the entry specified by that key.
      • removeAll

        @Deprecated
        Map<K,​V> removeAll​(@NonNull java.util.function.BiPredicate<? super K,​? super V> predicate)
        Deprecated.
        Returns a new Map consisting of all elements which do not satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • removeAll

        Map<K,​V> removeAll​(@NonNull java.lang.Iterable<? extends K> keys)
        Removes the mapping for a key from this map if it is present.
        Parameters:
        keys - keys are to be removed from the map
        Returns:
        A new Map containing these elements without the entries specified by that keys.
      • removeKeys

        @Deprecated
        Map<K,​V> removeKeys​(@NonNull java.util.function.Predicate<? super K> predicate)
        Deprecated.
        Returns a new Map consisting of all elements with keys which do not satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test keys of elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • removeValues

        @Deprecated
        Map<K,​V> removeValues​(@NonNull java.util.function.Predicate<? super V> predicate)
        Deprecated.
        Returns a new Map consisting of all elements with values which do not satisfy the given predicate.
        Parameters:
        predicate - the predicate used to test values of elements
        Returns:
        a new Map
        Throws:
        java.lang.NullPointerException - if predicate is null
      • scanLeft

        default <U> Seq<U> scanLeft​(U zero,
                                    @NonNull java.util.function.BiFunction<? super U,​? super Tuple2<K,​V>,​? extends U> operation)
        Description copied from interface: Traversable
        Produces a collection containing cumulative results of applying the operator from left to right.

        Will not terminate for infinite collections. The results may vary across runs unless the collection is ordered.

        Specified by:
        scanLeft in interface Traversable<K>
        Type Parameters:
        U - the type of the resulting elements
        Parameters:
        zero - the initial value
        operation - a binary operator applied to the intermediate result and each element
        Returns:
        a new Traversable containing the cumulative results
      • scanRight

        default <U> Seq<U> scanRight​(U zero,
                                     @NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super U,​? extends U> operation)
        Description copied from interface: Traversable
        Produces a collection containing cumulative results of applying the operator from right to left.

        The head of the resulting collection is the last cumulative result. Will not terminate for infinite collections. Results may vary across runs unless the collection is ordered.

        Specified by:
        scanRight in interface Traversable<K>
        Type Parameters:
        U - the type of the resulting elements
        Parameters:
        zero - the initial value
        operation - a binary operator applied to each element and the intermediate result
        Returns:
        a new Traversable containing the cumulative results
      • toJavaMap

        java.util.Map<K,​V> toJavaMap()
        Converts this Vavr Map to a java.util.Map while preserving characteristics like insertion order (LinkedHashMap) and sort order (SortedMap).
        Returns:
        a new java.util.Map instance
      • transform

        default <U> U transform​(@NonNull java.util.function.Function<? super Map<K,​V>,​? extends U> f)
        Transforms this Map.
        Type Parameters:
        U - Type of transformation result
        Parameters:
        f - A transformation
        Returns:
        An instance of type U
        Throws:
        java.lang.NullPointerException - if f is null
      • unzip

        default Tuple2<Seq<K>,​Seq<V>> unzip()
        Unzips the entries of this Map by treating each key-value pair as an element, and splitting them into two separate Seq collections - one for keys and one for values.
        Returns:
        a Tuple2 containing two Seq collections: first with all keys, second with all values
      • unzip

        default <T1,​T2> Tuple2<Seq<T1>,​Seq<T2>> unzip​(@NonNull java.util.function.BiFunction<? super K,​? super V,​Tuple2<? extends T1,​? extends T2>> unzipper)
        Unzips the entries of this Map by mapping each key-value pair to a tuple. The unzipper function transforms each entry into a Tuple2, and then all first elements are collected into the first Seq and all second elements into the second Seq.
        Type Parameters:
        T1 - type of the first element in the resulting pairs
        T2 - type of the second element in the resulting pairs
        Parameters:
        unzipper - a function that maps key-value pairs of this Map to tuples
        Returns:
        a Tuple2 containing two Seq collections with the split elements
        Throws:
        java.lang.NullPointerException - if unzipper is null
      • unzip

        default <T1,​T2> Tuple2<Seq<T1>,​Seq<T2>> unzip​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​Tuple2<? extends T1,​? extends T2>> unzipper)
        Description copied from interface: Traversable
        Unzips the elements of this Traversable by mapping each element to a pair and splitting them into two separate Traversable collections.
        Specified by:
        unzip in interface Traversable<K>
        Type Parameters:
        T1 - type of the first element in the resulting pairs
        T2 - type of the second element in the resulting pairs
        Parameters:
        unzipper - a function that maps elements of this Traversable to pairs
        Returns:
        a Tuple2 containing two Traversable collections with the split elements
      • unzip3

        default <T1,​T2,​T3> Tuple3<Seq<T1>,​Seq<T2>,​Seq<T3>> unzip3​(@NonNull java.util.function.BiFunction<? super K,​? super V,​Tuple3<? extends T1,​? extends T2,​? extends T3>> unzipper)
        Unzips the entries of this Map by mapping each key-value pair to a triple. The unzipper function transforms each entry into a Tuple3, and then elements are distributed to respective Seq collections by their position in the tuple: all first elements into the first Seq, all second elements into the second Seq, and all third elements into the third Seq.
        Type Parameters:
        T1 - type of the first element in the resulting triples
        T2 - type of the second element in the resulting triples
        T3 - type of the third element in the resulting triples
        Parameters:
        unzipper - a function that maps key-value pairs of this Map to triples
        Returns:
        a Tuple3 containing three Seq collections with the split elements
        Throws:
        java.lang.NullPointerException - if unzipper is null
      • unzip3

        default <T1,​T2,​T3> Tuple3<Seq<T1>,​Seq<T2>,​Seq<T3>> unzip3​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​Tuple3<? extends T1,​? extends T2,​? extends T3>> unzipper)
        Description copied from interface: Traversable
        Unzips the elements of this Traversable by mapping each element to a triple and splitting them into three separate Traversable collections.
        Specified by:
        unzip3 in interface Traversable<K>
        Type Parameters:
        T1 - type of the first element in the resulting triples
        T2 - type of the second element in the resulting triples
        T3 - type of the third element in the resulting triples
        Parameters:
        unzipper - a function that maps elements of this Traversable to triples
        Returns:
        a Tuple3 containing three Traversable collections with the split elements
      • values

        Seq<V> values()
        Returns a new Seq that contains the values of this Map.
        
         // = Seq("a", "b", "c")
         HashMap.of(1, "a", 2, "b", 3, "c").values()
         
        Returns:
        a new Seq
      • valuesIterator

        default Iterator<V> valuesIterator()
        Returns the values in this map.
        
         // = Iterator.of("a", "b", "c")
         HashMap.of(1, "a", 2, "b", 3, "c").values()
         
        Returns:
        a new Iterator
      • withDefault

        @Deprecated
        default Function1<K,​V> withDefault​(@NonNull java.util.function.Function<? super K,​? extends V> defaultFunction)
        Deprecated.
        Will be removed
        Turns this map from a partial function into a total function that returns a value computed by defaultFunction for all keys absent from the map.
        Parameters:
        defaultFunction - function to evaluate for all keys not present in the map
        Returns:
        a total function from K to T
      • withDefaultValue

        @Deprecated
        default Function1<K,​V> withDefaultValue​(V defaultValue)
        Deprecated.
        Will be removed
        Turns this map from a partial function into a total function that returns defaultValue for all keys absent from the map.
        Parameters:
        defaultValue - default value to return for all keys not present in the map
        Returns:
        a total function from K to T
      • zip

        default <U> Seq<Tuple2<Tuple2<K,​V>,​U>> zip​(@NonNull java.lang.Iterable<? extends U> that)
        Description copied from interface: Traversable
        Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable. Pairing stops when either collection runs out of elements; any remaining elements in the longer collection are ignored.

        The length of the resulting Traversable is the minimum of the lengths of this Traversable and that.

        Specified by:
        zip in interface Traversable<K>
        Type Parameters:
        U - the type of elements in the second half of each pair
        Parameters:
        that - an Iterable providing the second element of each pair
        Returns:
        a new Traversable containing pairs of corresponding elements
      • zipWith

        default <U,​R> Seq<R> zipWith​(@NonNull java.lang.Iterable<? extends U> that,
                                           java.util.function.BiFunction<? super Tuple2<K,​V>,​? super U,​? extends R> mapper)
        Description copied from interface: Traversable
        Returns a Traversable by combining elements of this Traversable with elements of another Iterable using a mapping function. Pairing stops when either collection runs out of elements.

        The length of the resulting Traversable is the minimum of the lengths of this Traversable and that.

        Specified by:
        zipWith in interface Traversable<K>
        Type Parameters:
        U - the type of elements in the second parameter of the mapper
        R - the type of elements in the resulting Traversable
        Parameters:
        that - an Iterable providing the second parameter of the mapper
        mapper - a function that combines elements from this and that into a new element
        Returns:
        a new Traversable containing mapped elements
      • zipAll

        default <U> Seq<Tuple2<Tuple2<K,​V>,​U>> zipAll​(@NonNull java.lang.Iterable<? extends U> that,
                                                                  Tuple2<K,​V> thisElem,
                                                                  U thatElem)
        Description copied from interface: Traversable
        Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable, filling in placeholder elements when one collection is shorter than the other.

        The length of the resulting Traversable is the maximum of the lengths of this Traversable and that.

        If this Traversable is shorter than that, thisElem is used as a filler. Conversely, if that is shorter, thatElem is used.

        Specified by:
        zipAll in interface Traversable<K>
        Type Parameters:
        U - the type of elements in the second half of each pair
        Parameters:
        that - an Iterable providing the second element of each pair
        thisElem - the element used to fill missing values if this Traversable is shorter than that
        thatElem - the element used to fill missing values if that is shorter than this Traversable
        Returns:
        a new Traversable containing pairs of elements, including fillers as needed
      • zipWithIndex

        default Seq<Tuple2<Tuple2<K,​V>,​java.lang.Integer>> zipWithIndex()
        Description copied from interface: Traversable
        Zips this Traversable with its indices, starting at 0.
        Specified by:
        zipWithIndex in interface Traversable<K>
        Returns:
        a new Traversable containing each element paired with its index
      • zipWithIndex

        default <U> Seq<U> zipWithIndex​(@NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super java.lang.Integer,​? extends U> mapper)
        Description copied from interface: Traversable
        Zips this Traversable with its indices and maps the resulting pairs using the provided mapper.
        Specified by:
        zipWithIndex in interface Traversable<K>
        Type Parameters:
        U - the type of elements in the resulting Traversable
        Parameters:
        mapper - a function mapping an element and its index to a new element
        Returns:
        a new Traversable containing the mapped elements
      • distinct

        Map<K,​V> distinct()
        Description copied from interface: Traversable
        Returns a new Traversable containing the elements of this instance with all duplicates removed. Element equality is determined using equals.
        Specified by:
        distinct in interface Traversable<K>
        Returns:
        a new Traversable without duplicate elements
      • distinctBy

        Map<K,​V> distinctBy​(@NonNull java.util.Comparator<? super Tuple2<K,​V>> comparator)
        Description copied from interface: Traversable
        Returns a new Traversable containing the elements of this instance without duplicates, as determined by the given comparator.
        Specified by:
        distinctBy in interface Traversable<K>
        Parameters:
        comparator - a comparator used to determine equality of elements
        Returns:
        a new Traversable with duplicates removed
      • distinctBy

        <U> Map<K,​V> distinctBy​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends U> keyExtractor)
        Description copied from interface: Traversable
        Returns a new Traversable containing the elements of this instance without duplicates, based on keys extracted from elements using keyExtractor.

        The first occurrence of each key is retained in the resulting sequence.

        Specified by:
        distinctBy in interface Traversable<K>
        Type Parameters:
        U - the type of key
        Parameters:
        keyExtractor - a function to extract keys for determining uniqueness
        Returns:
        a new Traversable with duplicates removed based on keys
      • drop

        Map<K,​V> drop​(int n)
        Description copied from interface: Traversable
        Returns a new Traversable without the first n elements, or an empty instance if this contains fewer than n elements.
        Specified by:
        drop in interface Traversable<K>
        Parameters:
        n - the number of elements to drop
        Returns:
        a new instance excluding the first n elements
      • dropRight

        Map<K,​V> dropRight​(int n)
        Description copied from interface: Traversable
        Returns a new Traversable without the last n elements, or an empty instance if this contains fewer than n elements.
        Specified by:
        dropRight in interface Traversable<K>
        Parameters:
        n - the number of elements to drop from the end
        Returns:
        a new instance excluding the last n elements
      • dropUntil

        Map<K,​V> dropUntil​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Returns a new Traversable starting from the first element that satisfies the given predicate, dropping all preceding elements.
        Specified by:
        dropUntil in interface Traversable<K>
        Parameters:
        predicate - a condition tested on each element
        Returns:
        a new instance starting from the first element matching the predicate
      • dropWhile

        Map<K,​V> dropWhile​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Returns a new Traversable starting from the first element that does not satisfy the given predicate, dropping all preceding elements.

        This is equivalent to dropUntil(predicate.negate()), which is useful for method references that cannot be negated directly.

        Specified by:
        dropWhile in interface Traversable<K>
        Parameters:
        predicate - a condition tested on each element
        Returns:
        a new instance starting from the first element not matching the predicate
      • filter

        Map<K,​V> filter​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Returns a new traversable containing only the elements that satisfy the given predicate.
        Specified by:
        filter in interface Traversable<K>
        Parameters:
        predicate - the condition to test elements
        Returns:
        a traversable with elements matching the predicate
      • reject

        Map<K,​V> reject​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Returns a new traversable containing only the elements that do not satisfy the given predicate.

        This is equivalent to filter(predicate.negate()).

        Specified by:
        reject in interface Traversable<K>
        Parameters:
        predicate - the condition to test elements
        Returns:
        a traversable with elements not matching the predicate
      • groupBy

        <C> Map<C,​? extends Map<K,​V>> groupBy​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​? extends C> classifier)
        Description copied from interface: Traversable
        Groups elements of this Traversable based on a classifier function.
        Specified by:
        groupBy in interface Traversable<K>
        Type Parameters:
        C - The type of the group keys
        Parameters:
        classifier - A function that assigns each element to a group
        Returns:
        A map where each key corresponds to a group of elements
        See Also:
        Traversable.arrangeBy(Function)
      • grouped

        Iterator<? extends Map<K,​V>> grouped​(int size)
        Description copied from interface: Traversable
        Splits this Traversable into consecutive blocks of the given size.

        Let length be the number of elements in this Traversable:

        • If empty, the resulting Iterator is empty.
        • If size <= length, the resulting Iterator contains length / size blocks of size size and possibly a final smaller block of size length % size.
        • If size > length, the resulting Iterator contains a single block of size length.

        Examples:

         
         [].grouped(1) = []
         [].grouped(0) throws
         [].grouped(-1) throws
         [1,2,3,4].grouped(2) = [[1,2],[3,4]]
         [1,2,3,4,5].grouped(2) = [[1,2],[3,4],[5]]
         [1,2,3,4].grouped(5) = [[1,2,3,4]]
         
         

        Note: grouped(size) is equivalent to sliding(size, size).

        Specified by:
        grouped in interface Traversable<K>
        Parameters:
        size - the block size; must be positive
        Returns:
        an Iterator over blocks of elements
      • isDefinedAt

        @Deprecated
        default boolean isDefinedAt​(K key)
        Deprecated.
        Description copied from interface: PartialFunction
        Tests whether a value is contained in the function's domain.
        Specified by:
        isDefinedAt in interface PartialFunction<K,​V>
        Parameters:
        key - a potential input to the function
        Returns:
        true if the given value is contained in the function's domain, false otherwise
      • isDistinct

        default boolean isDistinct()
        Description copied from interface: Traversable
        Indicates whether this Traversable may contain only distinct elements.
        Specified by:
        isDistinct in interface Traversable<K>
        Returns:
        true if this Traversable may contain only distinct elements, false otherwise
      • init

        Map<K,​V> init()
        Description copied from interface: Traversable
        Returns all elements of this Traversable except the last one.

        This is the dual of Traversable.tail().

        Specified by:
        init in interface Traversable<K>
        Returns:
        a new instance containing all elements except the last
      • initOption

        Option<? extends Map<K,​V>> initOption()
        Description copied from interface: Traversable
        Returns all elements of this Traversable except the last one, wrapped in an Option.

        This is the dual of Traversable.tailOption().

        Specified by:
        initOption in interface Traversable<K>
        Returns:
        Some(traversable) if non-empty, or None if this Traversable is empty
      • orElse

        Map<K,​V> orElse​(java.lang.Iterable<? extends Tuple2<K,​V>> other)
        Description copied from interface: Traversable
        Returns this Traversable if it is non-empty; otherwise, returns the given alternative.
        Specified by:
        orElse in interface Traversable<K>
        Parameters:
        other - an alternative Traversable to return if this is empty
        Returns:
        this Traversable if non-empty, otherwise other
      • orElse

        Map<K,​V> orElse​(@NonNull java.util.function.Supplier<? extends java.lang.Iterable<? extends Tuple2<K,​V>>> supplier)
        Description copied from interface: Traversable
        Returns this Traversable if it is non-empty; otherwise, returns the result of evaluating the given supplier.
        Specified by:
        orElse in interface Traversable<K>
        Parameters:
        supplier - a supplier of an alternative Traversable if this is empty
        Returns:
        this Traversable if non-empty, otherwise the result of supplier.get()
      • partition

        Tuple2<? extends Map<K,​V>,​? extends Map<K,​V>> partition​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Splits this Traversable into two partitions according to a predicate.

        The first partition contains all elements that satisfy the predicate, and the second contains all elements that do not. The original iteration order is preserved.

        Specified by:
        partition in interface Traversable<K>
        Parameters:
        predicate - a predicate used to classify elements
        Returns:
        a Tuple2 containing the two resulting Traversable instances
      • peek

        Map<K,​V> peek​(@NonNull java.util.function.Consumer<? super Tuple2<K,​V>> action)
        Description copied from interface: Value
        Performs the given action on the first element if this is an eager implementation. Performs the given action on all elements (the first immediately, successive deferred), if this is a lazy implementation.
        Specified by:
        peek in interface Traversable<K>
        Specified by:
        peek in interface Value<K>
        Parameters:
        action - The action that will be performed on the element(s).
        Returns:
        this instance
      • replace

        Map<K,​V> replace​(@NonNull Tuple2<K,​V> currentElement,
                               @NonNull Tuple2<K,​V> newElement)
        Description copied from interface: Traversable
        Replaces the first occurrence of currentElement with newElement, if it exists.
        Specified by:
        replace in interface Traversable<K>
        Parameters:
        currentElement - the element to be replaced
        newElement - the replacement element
        Returns:
        a new Traversable with the first occurrence of currentElement replaced by newElement
      • replaceValue

        Map<K,​V> replaceValue​(K key,
                                    V value)
        Replaces the entry for the specified key only if it is currently mapped to some value.
        Parameters:
        key - the key of the element to be substituted.
        value - the new value to be associated with the key
        Returns:
        a new map containing key mapped to value if key was contained before. The old map otherwise.
      • replace

        Map<K,​V> replace​(K key,
                               V oldValue,
                               V newValue)
        Replaces the entry for the specified key only if currently mapped to the specified value.
        Parameters:
        key - the key of the element to be substituted.
        oldValue - the expected current value that the key is currently mapped to
        newValue - the new value to be associated with the key
        Returns:
        a new map containing key mapped to newValue if key was contained before and oldValue matched. The old map otherwise.
      • replaceAll

        Map<K,​V> replaceAll​(@NonNull java.util.function.BiFunction<? super K,​? super V,​? extends V> function)
        Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception.
        Parameters:
        function - function transforming key and current value to a new value
        Returns:
        a new map with the same keySet but transformed values.
      • replaceAll

        Map<K,​V> replaceAll​(@NonNull Tuple2<K,​V> currentElement,
                                  Tuple2<K,​V> newElement)
        Description copied from interface: Traversable
        Replaces all occurrences of currentElement with newElement.
        Specified by:
        replaceAll in interface Traversable<K>
        Parameters:
        currentElement - the element to be replaced
        newElement - the replacement element
        Returns:
        a new Traversable with all occurrences of currentElement replaced by newElement
      • retainAll

        Map<K,​V> retainAll​(@NonNull java.lang.Iterable<? extends Tuple2<K,​V>> elements)
        Description copied from interface: Traversable
        Retains only the elements from this Traversable that are contained in the given elements.
        Specified by:
        retainAll in interface Traversable<K>
        Parameters:
        elements - the elements to keep
        Returns:
        a new Traversable containing only the elements present in elements, in their original order
      • scan

        Map<K,​V> scan​(@NonNull Tuple2<K,​V> zero,
                            @NonNull java.util.function.BiFunction<? super Tuple2<K,​V>,​? super Tuple2<K,​V>,​? extends Tuple2<K,​V>> operation)
        Description copied from interface: Traversable
        Computes a prefix scan of the elements of this Traversable.

        The neutral element zero may be applied more than once.

        Specified by:
        scan in interface Traversable<K>
        Parameters:
        zero - the neutral element for the operator
        operation - an associative binary operator
        Returns:
        a new Traversable containing the prefix scan of the elements
      • slideBy

        Iterator<? extends Map<K,​V>> slideBy​(@NonNull java.util.function.Function<? super Tuple2<K,​V>,​?> classifier)
        Description copied from interface: Traversable
        Partitions this Traversable into consecutive non-overlapping windows according to a classification function.

        Each window contains elements with the same class, as determined by classifier. Two consecutive elements belong to the same window only if classifier returns equal values for both. Otherwise, the current window ends and a new window begins with the next element.

        Examples:

        
         [].slideBy(Function.identity()) = []
         [1,2,3,4,4,5].slideBy(Function.identity()) = [[1],[2],[3],[4,4],[5]]
         [1,2,3,10,12,5,7,20,29].slideBy(x -> x / 10) = [[1,2,3],[10,12],[5,7],[20,29]]
         
        Specified by:
        slideBy in interface Traversable<K>
        Parameters:
        classifier - A function classifying elements into groups
        Returns:
        An Iterator of windows (grouped elements)
      • sliding

        Iterator<? extends Map<K,​V>> sliding​(int size)
        Description copied from interface: Traversable
        Slides a window of a given size over this Traversable with a step size of 1.

        This is equivalent to calling Traversable.sliding(int, int) with a step size of 1.

        Specified by:
        sliding in interface Traversable<K>
        Parameters:
        size - a positive window size
        Returns:
        An Iterator of windows, each containing up to size elements
      • sliding

        Iterator<? extends Map<K,​V>> sliding​(int size,
                                                   int step)
        Description copied from interface: Traversable
        Slides a window of a specific size with a given step over this Traversable.

        Examples:

        
         [].sliding(1, 1) = []
         [1,2,3,4,5].sliding(2, 3) = [[1,2],[4,5]]
         [1,2,3,4,5].sliding(2, 4) = [[1,2],[5]]
         [1,2,3,4,5].sliding(2, 5) = [[1,2]]
         [1,2,3,4].sliding(5, 3) = [[1,2,3,4],[4]]
         
        Specified by:
        sliding in interface Traversable<K>
        Parameters:
        size - a positive window size
        step - a positive step size
        Returns:
        an Iterator of windows with the given size and step
      • span

        Tuple2<? extends Map<K,​V>,​? extends Map<K,​V>> span​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Splits this Traversable into a prefix and remainder according to the given predicate.

        The first element of the returned Tuple is the longest prefix of elements satisfying predicate, and the second element is the remaining elements.

        Specified by:
        span in interface Traversable<K>
        Parameters:
        predicate - a predicate used to determine the prefix
        Returns:
        a Tuple containing the prefix and remainder
      • tail

        Map<K,​V> tail()
        Description copied from interface: Traversable
        Returns a new Traversable without its first element.
        Specified by:
        tail in interface Traversable<K>
        Returns:
        a new Traversable containing all elements except the first
      • tailOption

        Option<? extends Map<K,​V>> tailOption()
        Description copied from interface: Traversable
        Returns a new Traversable without its first element as an Option.
        Specified by:
        tailOption in interface Traversable<K>
        Returns:
        Some(traversable) if non-empty, otherwise None
      • take

        Map<K,​V> take​(int n)
        Description copied from interface: Traversable
        Returns the first n elements of this Traversable, or all elements if n exceeds the length.

        Equivalent to sublist(0, max(0, min(length(), n))), but safe for n < 0 or n > length().

        If n < 0, an empty instance is returned. If n > length(), the full instance is returned.

        Specified by:
        take in interface Traversable<K>
        Parameters:
        n - the number of elements to take
        Returns:
        a new Traversable containing the first n elements
      • takeRight

        Map<K,​V> takeRight​(int n)
        Description copied from interface: Traversable
        Returns the last n elements of this Traversable, or all elements if n exceeds the length.

        Equivalent to sublist(max(0, length() - n), length()), but safe for n < 0 or n > length().

        If n < 0, an empty instance is returned. If n > length(), the full instance is returned.

        Specified by:
        takeRight in interface Traversable<K>
        Parameters:
        n - the number of elements to take from the end
        Returns:
        a new Traversable containing the last n elements
      • takeUntil

        Map<K,​V> takeUntil​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Takes elements from this Traversable until the given predicate holds for an element.

        Equivalent to takeWhile(predicate.negate()), but useful when using method references that cannot be negated directly.

        Specified by:
        takeUntil in interface Traversable<K>
        Parameters:
        predicate - a condition tested sequentially on the elements
        Returns:
        a new Traversable containing all elements before the first one that satisfies the predicate
      • takeWhile

        Map<K,​V> takeWhile​(@NonNull java.util.function.Predicate<? super Tuple2<K,​V>> predicate)
        Description copied from interface: Traversable
        Takes elements from this Traversable while the given predicate holds.
        Specified by:
        takeWhile in interface Traversable<K>
        Parameters:
        predicate - a condition tested sequentially on the elements
        Returns:
        a new Traversable containing all elements up to (but not including) the first one that does not satisfy the predicate