regexp:
Match regular expression
Description
Returns the positions of substrings that match the regular expression.
Usage
regexp(s, pat, ignorecase = FALSE, once = FALSE, split = FALSE)
regexpi(s, pat, once = FALSE, split = FALSE)
Arguments
s
Character string, i.e. of length 1.
pat
Matching pattern as character string.
ignorecase
Logical: whether case should be ignored;
default: FALSE
.
once
Logical: whether the first are all occurrences should be found;
default: all.
split
Logical: should the string be splitted at the occurrences of
the pattern?; default: no.
Value
A list with components start
and end
as numeric vectors
indicating the start and end positions of the matches.match
contains each exact match, and split
contains the
character vector of splitted strings.If no match is found all components will be NULL
, except
split
that will contain the whole string if split = TRUE
.
Details
Returns the start and end positions and the exact value of substrings
that match the regular expression. If split
is choosen, the
splitted strings will also be returned.
Examples
s <- "bat cat can car COAT court cut ct CAT-scan"
pat <- 'c[aeiou]+t'
regexp(s, pat)
regexpi(s, pat)