Prepare a pattern for grep — complete

Prepare a pattern from a vector of characters. It particularly useful to find files of given extension within a vector of names.

Usage

complete_pattern(x, begin = FALSE, ending = FALSE, extension = FALSE)

Arguments

x: character, vector of patterns to be completed
begin: logical, should the pattern be at the beginning of strings
ending: logical, should the pattern be at the end of strings
extension: logical, should the pattern considered as an extension with a starting dot

Value

character of length one. To each element of x, it is firts applied transformation given by begin, ending and extention. Then, it is collapsed with "|". It can be used in a grep call.

Examples

extension = c("zip", "7z")
complete_pattern(extension)
#> [1] "zip|7z"
complete_pattern(extension, extension = TRUE)
#> [1] "[.]zip|[.]7z"
complete_pattern(extension, ending = TRUE)
#> [1] "zip$|7z$"