Before see tables, I want to show you a summary of the tables. Look following mind map:
| \a | Alert, \x07 |
| \b | Backspace, \x08, supported only in character class |
| \e | Esc, \x1B |
| \n | Newline, \x0A |
| \r | Carriage return, \x0D |
| \f | Form feed, \x0C |
| \t | Horizontal tab, \x09 |
| \octal | character specified by a three-digit octal code |
| \xhex | character specified by a one- or two digit hexadecimal code |
| \x{hex} | character specified by any hexadecimal code |
| \cchar | Named control character |
| [...] | A single character listed or contained within a listed range |
| [^...] | A single character not listed and not contained within a listed range |
| [:class:] | POSIX-style character class (valid only within a regex character class) |
| . | Any character excep newline (unless single-line mode, /s) |
| \C | One byte (this might corrupt a Unicode character stream however) |
| \w | Word character, [a-zA-Z0-9_] |
| \W | Nonword character, [^a-zA-Z0-9_] |
| \d | Digit character, [0-9] |
| \D | Nondigit character |
| \s | Whitespace character, [\n\r\f\t] |
| \S | Nonwhitespace character, [^\n\r\f\t] |
| ^ | Start of string, or the point after any newline if in multiline match mode, /m |
| \A | Start of search string, in all match modes |
| $ | End of search string, or the point before a string-ending newline, or before any newline if in multiline match mode, /m |
| \Z | End of string, or the point before a string-ending newline, in any match mode |
| \z | End of string, in any match mode |
| \G | Begining of current search |
| \b | Word boundary; position between a word character (\w), and a nonword character (\W), the start of the string, or the end of the string |
| \B | Not-word-bounday |
| (?=...) | Positive lookahead |
| (?!...) | Negative lookahead |
| (?<=...) | Positive lookbehind |
| (? | Negative lookbehind |
| i | Case-insensitive matching |
| m | ^ and $ match next to embedded \n |
| s | Dot(.) matches newline |
| x | Ignore whitespace, and allow comments (#) in pattern |
| U | Inverts greediness of all quantifies: * becomes lazy, and *? greedy |
| A | Force match to start at beginning of subject string |
| D | Force $ to match end of string instead of before the string ending newline. Overriden by multiline mode |
| u | Treat regular expressin and subject strings as strings of multibyte UTF-8 characters |
| (?mode) | Turn listed modes (one or more of imsxU) on for the rest of the subexpression |
| (?-mode) | Turn listed modes (one or more of imsxU) off for the rest of the subexpression |
| (?mode:...) | Turn mode (xsmi) on within parentheses |
| (?-mode:...) | Turn mode (xsmi) off within parentheses |
| (?#...) | Treat substring as a comment |
| (#...) | Rest of line is treated as a comment in x mode |
| \Q | Quotes all following regex metacharacters |
| \E | Ends a span started with \Q |
| (...) | Group subpattern and capture submatch into \1, \2, ... |
| (?P...) | Group subpattern, and capture submatch into named capture group, name |
| \n | Contains the results of the nth earlier submatch from a parentheses capture group, or a named capture group |
| (?:...) | Groups subpattern, but does not capture submatch |
| (?>...) | Atomic grouping |
| ...|... | Try subpatterns in alternation |
| * | Match 0 or more times |
| + | Match 1 or more times |
| ? | Match 1 or 0 times |
| {n} | Match exactly n times |
| {n,} | Match exactly n times |
| {x,y} | Match at least x times, but no more than y times |
| *? | Match 0 or more times, but as few times as possible |
| +? | Match 1 or more times, but as few times as possible |
| ?? | Match 0 or 1 times, but as few times as possible |
| {n,}? | Match at least n times, but as few times as possible |
| {x,y}? | Match at least x times, no more than y times, and as few times as possible |
| *+ | Match 0 or more times, and never backtrack |
| ++ | Match 1 or more times, and never backtrack |
| ?+ | Match 0 or 1 times, and never backtrack |
| {n,}+ | Match at least n times, and never backtrack |
| {x,y}+ | Match at least x times, no more than y times, and never backtrack |
| (?(condition)...|...) | Match with if-then-else pattern. The condition can be the number of a capture group, or a lookahead or lookbehind construct |
| (?(condition)...) | Match with if-then pattern. The condition can be the number of a capture group, or a lookahead or lookbehind construct |
