qdapRegex 0.5.0

Group Regular Expressions

Usage

group(..., left = "(", right = ")", dictionary = getOption("regex.library"))

Arguments

left
A single length character vector to use as the left bound.
right
A single length character vector to use as the right bound.
dictionary
A dictionary of canned regular expressions to search within.
...
Regular expressions to add grouping parenthesis to a named expression from the default regular expression dictionary prefixed with single at (@) (e.g., "@rm_hash") or a regular expression from regex_supplement dictionary prefixed with an at (@) (e.g., "@time_12_hours").

Value

Returns a single string of regular expressions with grouping parenthesis added.

Description

group - A wrapper for paste(collapse="|") that also searches the default and supplemental (regex_supplement) dictionaries for regular expressions before pasting them together with a pipe (|) separator.

Examples

group(LETTERS)



 [1] "(A)" "(B)" "(C)" "(D)" "(E)" "(F)" "(G)" "(H)" "(I)" "(J)" "(K)" "(L)" "(M)" "(N)" "(O)" "(P)" "(Q)" "(R)" "(S)" "(T)" "(U)"
[22] "(V)" "(W)" "(X)" "(Y)" "(Z)"



group(1)



[1] "(1)"




(grouped <- group("(the|them)\\b", "@rm_zip"))



[1] "((the|them)\\b)"                    "((?<!\\d)\\d{5}(?:[ -]\\d{4})?\\b)"



pastex(grouped)



[1] "((the|them)\\b)|((?<!\\d)\\d{5}(?:[ -]\\d{4})?\\b)"