filesstrings (version 0.4.0)

StrAfterNth: Text before or after \(n\)th occurrence of pattern.

Description

Extract the part of a string which is before or after the \(n\)th occurrence of a specified pattern, vectorised over the string. One can also choose \(n\) to be the last occurrence of the pattern. See argument n.

Usage

StrAfterNth(strings, pattern, n)
StrBeforeNth(strings, pattern, n)

Arguments

strings

A character vector.

pattern

A regular expression.

n

A natural number to identify the \(n\)th occurrence This can be negatively indexed, so if you wish to select the last occurrence, you need n = -1, for the second-last, you need n = -2 and so on.

Value

A character vector of the desired strings.

Examples

string <- "ab..cd..de..fg..h"
StrAfterNth(string, "\\.\\.", 3)
StrBeforeNth(string, "e", 1)
StrBeforeNth(string, "\\.", -3)
StrBeforeNth(string, ".", -3)
StrBeforeNth(rep(string, 2), fixed("."), -3)