Vector-setops {S4Vectors} | R Documentation

## Set operations on vector-like objects

### Description

Perform set operations on Vector objects.

### Usage

    ## S4 method for signature 'Vector,Vector'
    union(x, y)

    ## S4 method for signature 'Vector,Vector'
    intersect(x, y)

    ## S4 method for signature 'Vector,Vector'
    setdiff(x, y)

    ## S4 method for signature 'Vector,Vector'
    setequal(x, y)

### Arguments

`x, y` | Vector-like objects.

### Details

The `union`, `intersect`, and `setdiff` methods for Vector objects return a Vector object containing respectively the union, intersection, and (asymmetric!) difference of the 2 sets of vector elements in `x` and `y`. The `setequal` method for Vector objects checks for set equality between `x` and `y`.

They're defined as follow:

        setMethod("union", c("Vector", "Vector"),
            function(x, y) unique(c(x, y))
        )
        setMethod("intersect", c("Vector", "Vector"),
            function(x, y) unique(x[x %in% y])
        )
        setMethod("setdiff", c("Vector", "Vector"),
            function(x, y) unique(x[!(x %in% y)])
        )
        setMethod("setequal", c("Vector", "Vector"),
            function(x, y) all(x %in% y) && all(y %in% x)
        )

so they work out-of-the-box on Vector objects for which `c`, `unique`, and `%in%` are defined.

### Value

`union` returns a Vector object obtained by appending to `x` the elements in `y` that are not already in `x`.

`intersect` returns a Vector object obtained by keeping only the elements in `x` that are also in `y`.

`setdiff` returns a Vector object obtained by dropping from `x` the elements that are in `y`.

`setequal` returns `TRUE` if `x` and `y` contain the same sets of vector elements and `FALSE` otherwise.

`union`, `intersect`, and `setdiff` propagate the names and metadata columns of their first argument (`x`).

### Author(s)

Hervé Pagès

### See Also

- Vector-comparison for comparing and ordering vector-like objects.

- Vector-merge for merging vector-like objects.

- Vector objects.

- `BiocGenerics::union`, `BiocGenerics::intersect`, and `BiocGenerics::setdiff` in the BiocGenerics package for general information about these generic functions.

### Examples

    ## See ?`Hits-setops` for some examples.

[Package S4Vectors version 0.18.3 Index]