sortAscii {geecc} | R Documentation

## Optimized operations of sets of character-vectors

### Description

Sort and use pre-sorted character vectors in set-operations

### Usage

    sortAscii(x)
    intersectPresort(pop, x)
    setdiffPresort(pop, x)

### Arguments

`x` | an unsorted vectors of strings
`pop` | a sorted vector of strings

### Details

By default, sorting is done lexicographically in R. The routine `sortAscii` does sorting accoring to the ASCII-order as done in C/C++.

For routines `intersectPresort` and `setdiffPresort` the first argument has to be sorted according to ASCII-order. This first argument is expected to be large compared to the second argument. Both functions are wrappers for optimized C++-functions performing the set-operation.

### Value

An character-vector. In case of `intersectPresort` and `setdiffPresort`, these vectors are unnamed.

### Examples

    AA <- matrix( sample( c(LETTERS, letters), 10*30000, rep=TRUE ), ncol=10 )
    A <- unique(apply(AA, 1, paste, collapse=""))
    B <- sample(AA, 100, replace=FALSE); B <- c(B, "1234")

    res <- intersectPresort( sortAscii(A), B )

[Package geecc version 1.20.0 Index]