filesstrings (version 2.0.1)

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

Description

Extract the part of a string which is before or after the nth occurrence of a specified pattern, vectorized over the string. n can be negatively indexed. See 'Arguments'.

Usage

str_after_nth(strings, pattern, n)
str_after_first(strings, pattern)
str_after_last(strings, pattern)
str_before_nth(strings, pattern, n)
str_before_first(strings, pattern)
str_before_last(strings, pattern)

Arguments

strings

A character vector.

pattern

A regular expression.

n

A natural number to identify the \(n\)th occurrence (defaults to first (n = 1)). 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.

Details

• str_after_first(...) is just str_after_nth(..., n = 1).

• str_after_last(...) is just str_after_nth(..., n = -1).

• str_before_first(...) is just str_before_nth(..., n = 1).

• str_before_last(...) is just str_before_nth(..., n = -1).

Examples

# NOT RUN {
string <- "ab..cd..de..fg..h"
str_after_nth(string, "\\.\\.", 3)
str_before_nth(string, "e", 1)
str_before_nth(string, "\\.", -3)
str_before_nth(string, ".", -3)
str_before_nth(rep(string, 2), fixed("."), -3)
# }

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