Backreferences
Backreferences for replacement operations. These are used by replacement
functions such as sub and
stri_replace_first_regex, and by the stringi
and stringr match functions such as
stri_match_first_regex.
REF1 REF2 REF3 REF4 REF5 REF6 REF7 REF8 REF9 ICU_REF1 ICU_REF2 ICU_REF3 ICU_REF4 ICU_REF5 ICU_REF6 ICU_REF7 ICU_REF8 ICU_REF9
An object of class regex (inherits from character) of length 1.
capture, for creating capture groups that can be
referred to.
# For R's PCRE and Perl engines
REF1
REF2
# and so on, up to
REF9
# For stringi/stringr's ICU engine
ICU_REF1
ICU_REF2
# and so on, up to
ICU_REF9
# Usage
sub("a(b)c(d)", REF1 %R% REF2, "abcd")
stringi::stri_replace_first_regex("abcd", "a(b)c(d)", ICU_REF1 %R% ICU_REF2)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.