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  • Regular Expressions Cheat Sheet by Dave Child (DaveChild) via cheatography.com/1/cs/5/ Regular Expressions Anchors Regular Expressions Quantifiers Regular Expressions Groups and Ranges ^ Start of string, or start of line in multi-line pattern * 0 or more . Any character except new line (n) A Start of string + 1 or more (a|b) a or b $ End of string, or end of line in multi-line pattern ? 0 or 1 (...) Group Z End of string {3} Exactly 3 (?:...) Passive (non-capturing) group b Word boundary {3,} 3 or more [abc] Range (a or b or c) B Not word boundary {3,5} 3, 4 or 5 [^abc] Not a or b or c < Start of word Add a ? to a quantifier to make it ungreedy. [a-q] Letter from a to q > End of word [A-Q] Upper case letter from A to Q Regular Expressions Escape Sequences [0-7] Digit from 0 to 7 Regular Expressions Character Classes Escape following character n nth group/subpattern c Control character Q Begin literal sequence Ranges are inclusive. s White space E End literal sequence S Not white space "Escaping" is a way of treating characters which have Regular Expressions Pattern Modifiers d Digit a special meaning in regular expressions literally, g Global match D Not digit rather than as special characters. i Case-insensitive w Word m Multiple lines W Not word s Treat string as single line x Hexadecimal digit x Allow comments and white space in pattern O Octal digit e Evaluate replacement U Ungreedy pattern Regular Expression Common Metacharacters ^ [ . $ { * ( + Regular Expressions POSIX ) | ? [:upper:] Upper case letters < > [:lower:] Lower case letters The escape character is usually the backslash - . [:alpha:] All letters [:alnum:] Digits and letters [:digit:] Digits [:xdigit:] Hexadecimal digits [:punct:] Punctuation [:blank:] Space and tab [:space:] Blank characters [:cntrl:] Control characters [:graph:] Printed characters [:print:] Printed characters and spaces [:word:] Digits, letters and underscore Regular Expressions Special Characters n New line r Carriage return t Tab v Vertical tab f Form feed xxx Octal character xxx xhh Regular Expressions String Replacement $n nth non-passive group $2 "xyz" in /^(abc(xyz))$/ $1 "xyz" in /^(?:abc)(xyz)$/ $` Before matched string $' After matched string $+ Last matched string $& Entire matched string Hex character hh Some regex implementations use instead of $. Regular Expressions Assertions ?= Lookahead assertion ?! Negative lookahead ?<= Lookbehind assertion ?!= or ?<! Negative lookbehind ?> Once-only Subexpression ?() Condition [if then] ?()| Condition [if then else] ?# Comment Cheatographer Cheat Sheet Sponsor Dave Child (DaveChild) This cheat sheet was published on 19th October, 2011 FeedbackFair, increase your conversion rate today! cheatography.com/davechild/ and was last updated on 14th November, 2012. Try it free! www.addedbytes.com http://www.FeedbackFair.com