R: Find overlapping regular expression matches.

refindall {pracma} | R Documentation

## Find overlapping regular expression matches.

### Description

Find overlapping matches for a regular expression.

### Usage

    refindall(s, pat, over = 1, ignorecase = FALSE)

### Arguments

`s` | Single character string.
`pat` | Regular expression.
`over` | Natural number, indication how many steps to go forward after a match; defaults to 1.
`ignorecase` | logical, whether to ignore case.

### Details

Returns the starting position of all — even overlapping — matches of the regular expression `pat` in the character string `s`.

The syntax for pattern matching has to be PERL-like.

### Value

A numeric vector with the indices of starting positions of all matches.

### Note

This effect can also be reached with the R function gregexpr(), see the example below.

### See Also

`regexp`

### Examples

    refindall("ababababa", 'aba')
    gregexpr('a(?=ba)', "ababababa", perl=TRUE)

    refindall("AbababaBa", 'aba')
    refindall("AbababaBa", 'aba', ignorecase = TRUE)

[Package pracma version 2.0.4 Index]