From 6dcf5b16ede115836d227da05188ee0260f28465 Mon Sep 17 00:00:00 2001 From: Paul Trowbridge Date: Tue, 4 Oct 2022 10:04:56 -0400 Subject: [PATCH] regex cheat sheet --- regex.md | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 regex.md diff --git a/regex.md b/regex.md new file mode 100644 index 0000000..bcbd6d1 --- /dev/null +++ b/regex.md @@ -0,0 +1,53 @@ +[https://cheatography.com/davechild/cheat-sheets/regular-expressions/](https://cheatography.com/davechild/cheat-sheets/regular-expressions/) + +``` +Anchors Quantifiers Groups and Ranges + +^ Start of string, or start of line in multi-line pattern * 0 or more {3} Exactly 3 . Any character except new line (\n) +\A Start of string + 1 or more {3,} 3 or more (a|b) a or b +$ End of string, or end of line in multi-line pattern ? 0 or 1 {3,5} 3, 4 or 5 (...) Group +\Z End of string Add a ? to a quantifier to make it ungreedy. (?:...) Passive (non-capturing) group +\b Word boundary [abc] Range (a or b or c) +\B Not word boundary Escape Sequences [^abc] Not (a or b or c) +\< Start of word [a-q] Lower case letter from a to q +\> End of word \ Escape following character [A-Q] Upper case letter from A to Q + \Q Begin literal sequence [0-7] Digit from 0 to 7 +Character Classes \E End literal sequence \x Group/subpattern number "x" + Ranges are inclusive. +\c Control character +\s White space Pattern Modifiers +\S Not white space Common Metacharacters +\d Digit g Global match +\D Not digit ^ [ . $ i * Case-insensitive +\w Word { * ( \ m * Multiple lines +\W Not word + ) | ? s * Treat string as single line +\x Hexadecimal digit < > x * Allow comments and whitespace in pattern +\O Octal digit The escape character is usually \ e * Evaluate replacement + U * Ungreedy pattern +POSIX Special Characters * PCRE modifier + +[:upper:] Upper case letters \n New line String Replacement +[:lower:] Lower case letters \r Carriage return +[:alpha:] All letters \t Tab $n nth non-passive group +[:alnum:] Digits and letters \v Vertical tab $2 "xyz" in /^(abc(xyz))$/ +[:digit:] Digits \f Form feed $1 "xyz" in /^(?:abc)(xyz)$/ +[:xdigit:] Hexadecimal digits \xxx Octal character xxx $` Before matched string +[:punct:] Punctuation \xhh Hex character hh $' After matched string +[:blank:] Space and tab $+ Last matched string +[:space:] Blank characters $& Entire matched string +[:cntrl:] Control characters Some regex implementations use \ instead of $. +[:graph:] Printed characters +[:print:] Printed characters and spaces +[:word:] Digits, letters and underscore + +Assertions + +?= Lookahead assertion +?! Negative lookahead +?<= Lookbehind assertion +?!= or ? Once-only Subexpression +?() Condition [if then] +?()| Condition [if then else] +?# Comment +```