Regular expression | regular expression wiki
"Regex"redirectshere.Forthecomicbook,seeRe:Gex.SequenceofcharactersthatformsasearchpatternThematchresultsofthepatternAtleasttwospacesarematched,butonlyiftheyoccurdirectlyafteraperiod(.)andbeforeanuppercaseletter.Aregularexpression(shortenedasregexorregexp;[1]alsoreferredtoasrationalexpression)[2][3]isasequenceofcharactersthatdefineasearchpattern.Usuallysuchpatternsareusedbystringsearchingalgorithmsfor"find"or"findandreplace"operationsonstrings,orforinputvalidation.Itisatechniquedevelopedinth...
"Regex" redirects here. For the comic book, see Re:Gex.Sequence of characters that forms a search pattern
The match results of the pattern At least two spaces are matched, but only if they occur directly after a period (.) and before an uppercase letter.A regular expression (shortened as regex or regexp;[1] also referred to as rational expression)[2][3] is a sequence of characters that define a search pattern. Usually such patterns are used by string searching algorithms for "find" or "find and replace" operations on strings, or for input validation. It is a technique developed in theoretical computer science and formal language theory.
The concept arose in the 1950s when the American mathematician Stephen Cole Kleene formalized the description of a regular language. The concept came into common use with Unix text-processing utilities. Different syntaxes for writing regular expressions have existed since the 1980s, one being the POSIX standard and another, w...