| Feature | Syntax | Description | Example | .NET | Java | Perl | PCRE2 | PHP | Delphi | R | JavaScript | VBScript | XRegExp | Python | Ruby | std::regex | Boost | Tcl ARE | Oracle | XPath |
|---|
| Conditional |
?1yes:no through ?99yes:no |
Conditional referencing a numbered capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (y)?|n in yyn! with ?1yes:no yields yesyesno! |
no | no | no | no | no | no | no | no | no | no | no | no | no | all | no | no | no |
| Conditional |
(?1yes:no) through (?99yes:no) |
Conditional referencing a numbered capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (y)?|n in yyn! with (?1yes:no) yields yesyesno! |
no | no | no | no | no | no | no | no | no | no | no | no | no | all | no | no | no |
| Conditional |
(?10yes:no) through (?99yes:no) |
When there are fewer capturing groups than the 2-digit number, treat this as a single-digit conditional with the “yes” part starting with a literal number instead of as an invalid conditional. |
Replacing all matches of (y)?|n in yyn! with (?19yes:no) yields 9yes9yesno! |
n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | no | n/a | n/a | n/a |
| Conditional |
?{1}yes:no through ?{99}yes:no |
Conditional referencing a numbered capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (y)?|n in yyn! with ?{1}yes:no yields yesyesno! |
no | no | no | no | no | no | no | no | no | no | no | no | no | all
1.42–1.83 | no | no | no |
| Conditional |
(?{1}yes:no) through (?{99}yes:no) |
Conditional referencing a numbered capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (y)?|n in yyn! with (?{1}yes:no) yields yesyesno! |
no | no | no | no | no | no | no | no | no | no | no | no | no | all
1.42–1.83 | no | no | no |
| Conditional |
${1:+yes:no} through ${99:+yes:no} |
Conditional referencing a numbered capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (y)?|n in yyn! with ${1:+yes:no} yields yesyesno! |
no | no | no | extended | no | no | no | no | no | no | no | no | no | no | no | no | no |
| Conditional |
${1:-no} through ${99:-no} |
Conditional referencing a numbered capturing group. Inserts the text captured by the group if it participated or the contents of the conditional if it didn’t. |
Replacing all matches of (y)?|n in yyn! with ${1:-no} yields yyno! |
no | no | no | extended | no | no | no | no | no | no | no | no | no | no | no | no | no |
| Conditional |
Any numbered conditional |
A conditional that references the number of a capturing group that does not exist acts as a conditional to a group that never participates. |
Replacing all matches of (y)?|n in yyn! with (?9yes:no) yields nonono! |
n/a | n/a | n/a | extended error | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | all | n/a | n/a | n/a |
| Conditional |
$?{name}yes:no |
Conditional referencing a named capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (?'one'y)?|n in yyn! with ?{one}yes:no yields yesyesno! |
no | no | no | no | no | no | no | no | no | no | no | no | no | all
1.42–1.83 | no | no | no |
| Conditional |
(?{name}yes:no) |
Conditional referencing a named capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (?'one'y)?|n in yyn! with (?{one}yes:no) yields yesyesno! |
no | no | no | no | no | no | no | no | no | no | no | no | no | all
1.42–1.83 | no | no | no |
| Conditional |
${name:+yes:no} |
Conditional referencing a named capturing group. Inserts the “yes” part if the group participated or the “no” part if it didn’t. |
Replacing all matches of (?'one'y)?|n in yyn! with ${one:+yes:no} yields yesyesno! |
no | no | no | extended | no | no | no | no | no | no | no | no | no | no | no | no | no |
| Conditional |
${name:-no} |
Conditional referencing a named capturing group. Inserts the text captured by the group if it participated or the contents of the conditional if it didn’t. |
Replacing all matches of (?'one'y)?|n in yyn! with ${one:-no} yields yyno! |
no | no | no | extended | no | no | no | no | no | no | no | no | no | no | no | no | no |
| Conditional |
Any named conditional |
A conditional that references the name of a capturing group that does not exist is treated as literal text. |
Replacing all matches of (y)?|n in yn! with (?{name}yes:no) yields ?{name}yes:no?{name}yes:no! |
n/a | n/a | n/a | extended error | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | n/a | all
1.42–1.83 | n/a | n/a | n/a |
| Feature | Syntax | Description | Example | .NET | Java | Perl | PCRE2 | PHP | Delphi | R | JavaScript | VBScript | XRegExp | Python | Ruby | std::regex | Boost | Tcl ARE | Oracle | XPath |
|---|
