stri_opts_regex | R Documentation |
A convenience function to tune the ICU regular expressions
matcher's behavior, e.g., in stri_count_regex
and other stringi-search-regex functions.
stri_opts_regex(
case_insensitive,
comments,
dotall,
dot_all = dotall,
literal,
multiline,
multi_line = multiline,
unix_lines,
uword,
error_on_unknown_escapes,
time_limit = 0L,
stack_limit = 0L
)
case_insensitive |
logical; enables case insensitive matching [regex flag |
comments |
logical; allows white space and comments within patterns [regex flag |
dotall |
logical; if set, ' |
dot_all |
alias of |
literal |
logical; if set, treat the entire pattern as a literal string: metacharacters or escape sequences in the input sequence will be given no special meaning; note that in most cases you would rather use the stringi-search-fixed facilities in this case |
multiline |
logical; controls the behavior of ' |
multi_line |
alias of |
unix_lines |
logical; Unix-only line endings;
when enabled, only |
uword |
logical; Unicode word boundaries;
if set, uses the Unicode TR 29 definition of word boundaries;
warning: Unicode word boundaries are quite different from traditional
regex word boundaries. [regex flag |
error_on_unknown_escapes |
logical; whether to generate an error on unrecognized backslash escapes; if set, fail with an error on patterns that contain backslash-escaped ASCII letters without a known special meaning; otherwise, these escaped letters represent themselves |
time_limit |
integer; processing time limit, in ~milliseconds (but not precisely so, depends on the CPU speed), for match operations; setting a limit is desirable if poorly written regexes are expected on input; 0 for no limit |
stack_limit |
integer; maximal size, in bytes, of the heap storage available for the match backtracking stack; setting a limit is desirable if poorly written regexes are expected on input; 0 for no limit |
Note that some regex settings may be changed using ICU regex flags
inside regexes. For example, '(?i)pattern'
performs
a case-insensitive match of a given pattern,
see the ICU User Guide entry on Regular Expressions
in the References section or stringi-search-regex.
Returns a named list object; missing settings are left with default values.
Marek Gagolewski and other contributors
enum URegexpFlag
: Constants for Regular Expression Match Modes
– ICU4C API Documentation,
https://unicode-org.github.io/icu-docs/apidoc/dev/icu4c/uregex_8h.html
Regular Expressions – ICU User Guide, https://unicode-org.github.io/icu/userguide/strings/regexp.html
The official online manual of stringi at https://stringi.gagolewski.com/
Gagolewski M., stringi: Fast and portable character string processing in R, Journal of Statistical Software 103(2), 2022, 1-59, \Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v103.i02")}
Other search_regex:
about_search_regex
,
about_search
stri_detect_regex('ala', 'ALA') # case-sensitive by default
stri_detect_regex('ala', 'ALA', opts_regex=stri_opts_regex(case_insensitive=TRUE))
stri_detect_regex('ala', 'ALA', case_insensitive=TRUE) # equivalent
stri_detect_regex('ala', '(?i)ALA') # equivalent
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