php Programming Glossary: lookbehind
“vertical” regex matching in an ASCII “image” http://stackoverflow.com/questions/17039670/vertical-regex-matching-in-an-ascii-image must not proceed past the first X . We can do this via a lookbehind and lookahead. Perl only supports constant length lookbehind.. and lookahead. Perl only supports constant length lookbehind but has the K escape which provides similar semantics. Thus..
php regex: lookbehind and lookahead and greediness problem http://stackoverflow.com/questions/1731934/php-regex-lookbehind-and-lookahead-and-greediness-problem regex lookbehind and lookahead and greediness problem This should be simple..
Parsing command arguments in PHP http://stackoverflow.com/questions/17848618/parsing-command-arguments-in-php set the s modifier to match newlines with a dot . negative lookbehind check if there is no backslash preceding the next token ' match.. to remember if it's a single or a double one. The negative lookbehinds are there to make sure we don't match escaped quotes. 1 is.. is almost applicable for any language flavor that supports lookbehinds and backreferences. Of course this solution expects that the..
Merging two Regular Expressions to Truncate Words in Strings http://stackoverflow.com/questions/2682861/merging-two-regular-expressions-to-truncate-words-in-strings # begin capture group 1 . 1 x # match 1 x characters S # lookbehind match must end with non whitespace s # lookahead if the next..
PHP - Function To Find Links In Text http://stackoverflow.com/questions/3762666/php-function-to-find-links-in-text To solve your immediate problem you could add a negative lookbehind to your second regex http www. a zA Z0 9@ _ .~# ensures that..
PHP split string into integer element and string http://stackoverflow.com/questions/4537994/php-split-string-into-integer-element-and-string this question You can use preg_split using lookahead and lookbehind print_r preg_split '# d a z #i' 0982asdlkj prints Array 0 0982..
Php to replace @username with link to twitter account http://stackoverflow.com/questions/4766158/php-to-replace-username-with-link-to-twitter-account at the beginning . It can also be shorted using positive lookbehind as input preg_replace ' ^ s @ a z0 9_ i' ' a href http www.twitter.com..
PHP: remove `http://` from link title http://stackoverflow.com/questions/4875085/php-remove-http-from-link-title 42 a href http google.com google.com a It uses a negative lookbehind to make sure there is no href or href ' preceding it. See it..
php sentence boundaries detection http://stackoverflow.com/questions/5032210/php-sentence-boundaries-detection sentences on whitespace between them. # Begin positive lookbehind. . # Either an end of sentence punct . ' # or end of sentence.. . ' # or end of sentence punct and quote. # End positive lookbehind. # Begin negative lookbehind. Mr . # Skip either Mr. Mrs ... and quote. # End positive lookbehind. # Begin negative lookbehind. Mr . # Skip either Mr. Mrs . # or Mrs. Ms . # or Ms. Jr . #..
Regex ignore URL already in HTML tags http://stackoverflow.com/questions/9567836/regex-ignore-url-already-in-html-tags on Regexr To make it more general you can simplify your lookbehind to check only for b w w #~ . @ w See it on Regexr href is a.. for b w w #~ . @ w See it on Regexr href is a negative lookbehind assertion it ensures that there is no href before your pattern... from a non word to a word character. without this the lookbehind would be useless and it would match from the ttp ... on. share..
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