Regular expression syntax reference

RegEx syntax reference

Character	Description
`\`	Marks the next character as either a special character or a literal. For example: n matches the character n. "\n" matches a newline character. The sequence `\\` matches `\` and `\(` matches `(`.
`^`	Matches the beginning of input.
`$`	Matches the end of input.
`*`	Matches the preceding character zero or more times. For example, "zo" matches either z or zoo*.
`+`	Matches the preceding character one or more times. For example, "zo+" matches zoo but not z.
`?`	Matches the preceding character zero or one time. For example, `a?ve?` matches the `ve` in `never`.
`.`	Matches any single character except a newline character.
`(`subexpression`)`	Matches subexpression and remembers the match. If a part of a regular expression is enclosed in parentheses, that part of the regular expression is grouped together. Thus a regex operator can be applied to the entire group. If you need to use the matched substring within the same regular expression, you can retrieve it using the backreference `\num`, where `num = 1..n`. If you need to refer the matched substring somewhere outside the current regular expression (for example, in another regular expression as a replacement string), you can retrieve it using the dollar sign `$num`, where `num = 1..n`. If you need to include the parentheses characters into a subexpression, use `$` or `$`.
x `\|`y	Matches either x or y. For example, `z\|wood` matches z or wood. `(z\|w)oo` matches zoo or wood.
{`n`}	n is a non negative integer. Matches exactly n times. For example, `o{2}` does not match the o in Bob, but matches the first two o's in foooood.
{`n`,}	n is a non negative integer. Matches at least n times. For example, `o{2,}` does not match the o in Bob and matches all the o's in "foooood." `o{1,}` is equivalent to `o+`. `o{0,}` is equivalent to `o*`.
`{` n `,` m `}`	m and n are nonnegative integers. Matches at least n and at most m times. For example, `o{1,3}` matches the first three o's in "fooooood." `o{0,1}` is equivalent to `o?`.
`[`xyz`]`	A character set. Matches any one of the enclosed characters. For example, `[abc]` matches the a in plain.
`[^` xyz `]`	A negative character set. Matches any character not enclosed. For example, `[^abc]` matches the p in plain.
`[` a-z `]`	A range of characters. Matches any character in the specified range. For example, "[a-z]" matches any lowercase alphabetic character in the range a through z.
`[^` m-z `]`	A negative range characters. Matches any character not in the specified range. For example, `[^m-z]` matches any character not in the range m through z.
`\b`	Matches a word boundary, that is, the position between a word and a space. For example, `er\b` matches the er in never but not the er in verb.
`\B`	Matches a non-word boundary. `ear\B` matches the ear* in never early.
`\d`	Matches a digit character. Equivalent to `[0-9]`.
`\D`	Matches a non-digit character. Equivalent to `[^0-9]`.
`\f`	Matches a form-feed character.
`\n`	Matches a newline character.
`\r`	Matches a carriage return character.
`\s`	Matches any white space including space, tab, form-feed, and so on. Equivalent to `[ \f\n\r\t\v]`.
`\S`	Matches any nonwhite space character. Equivalent to `[^ \f\n\r\t\v]`.
`\t`	Matches a tab character.
`\v`	Matches a vertical tab character.
`\w`	Matches any word character including underscore. Equivalent to `[A-Za-z0 -9_]`. Use it in the search field.
`\W`	Matches any non-word character. Equivalent to `[^A-Za-z0-9_]`.
`\`num	Matches num, where num is a positive integer, denoting a reference back to remembered matches. For example, `(.)\1` matches two consecutive identical characters.
`\`n	Matches n, where n is an octal escape value. Octal escape values should be 1, 2, or 3 digits long. For example, `\11` and `\011` both match a tab character. `\0011` is the equivalent of `\001`&1. Octal escape values should not exceed 256. If they do, only the first two digits comprise the expression. Allows ASCII codes to be used in regular expressions.
`\x`n	Matches n, where n is a hexadecimal escape value. Hexadecimal escape values must be exactly two digits long. For example, `\x41` matches `A`. `\x041` is equivalent to `\x04`&`1`. Allows ASCII codes to be used in regular expressions.
`\$`	Finds a `$` character.
`\\$`	This regex entered in the search field, means that you are trying to find a `\` character at the end of the line.
`\l`	Changes the case of the next character to the lower case. Use this type of regex in the replace field.
`\u`	Changes the case of the next character to the upper case. Use this type of regex in the replace field.
`\L`	Changes the case of all the subsequent characters up to `\E` to the lower case. Use this type of regex in the replace field.
`\U`	Changes the case of all the subsequent characters up to `\E` to the upper case. Use this type of regex in the replace field.
`(?!)`	This is a pattern for "negative lookahead". For example, `A(?!B)` means that PhpStorm will search for `A`, but only if not followed by `B`.
`(?=)`	This is a pattern for "positive lookahead". For example, `A(?=B)` means that PhpStorm will search for `A`, but match if only followed by `B`.
`(?<=)`	This is a pattern for "positive lookbehind". For example, `(?<=B)A` means that PhpStorm will search for `A`, but only if there is `B` before it.
`(?<!)`	This is a pattern for "negative lookbehind". For example, `(?<!B)A` means that PhpStorm will search for `A`, but only if there is no `B` before it.