{"id":43803,"date":"2014-10-21T07:00:00","date_gmt":"2014-10-21T07:00:00","guid":{"rendered":"https:\/\/blogs.msdn.microsoft.com\/oldnewthing\/2014\/10\/21\/the-great-thing-about-regular-expression-languages-is-that-there-are-so-many-to-choose-from\/"},"modified":"2014-10-21T07:00:00","modified_gmt":"2014-10-21T07:00:00","slug":"the-great-thing-about-regular-expression-languages-is-that-there-are-so-many-to-choose-from","status":"publish","type":"post","link":"https:\/\/devblogs.microsoft.com\/oldnewthing\/20141021-00\/?p=43803","title":{"rendered":"The great thing about regular expression languages is that there are so many to choose from!"},"content":{"rendered":"

\nBefore you ask a question about regular expressions,\nyou should make sure you and your audience agree on\nwhich<\/i> regular expression language you are talking about.\n<\/p>\n

\nHere is a\n\nhandy table of which features are supported by\nwhich regular expression language<\/a>.\n<\/p>\n

\nYou can use that table to solve this customer’s problem:\n<\/p>\n

\n

\nI have a regular expression that works just fine when I test\nit in\n⟨insert regular expression testing tool, like\nRegExr<\/a>\nor\n\nRegexPlanet<\/a><\/i>⟩,\nbut I can’t get it to work in real life.\n<\/p>\n

\nC:\\> findstr \/r \/c:\"a(?!.*b)\" file.txt\n(prints no results!)<\/i>\nC:\\>\n<\/pre>\n
\nMy goal is to find all lines that contain an a<\/code>\nnot followed anywhere by a b<\/code>.\n<\/p>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"
Before you ask a question about regular expressions, you should make sure you and your audience agree on which regular expression language you are talking about. Here is a handy table of which features are supported by which regular expression language. You can use that table to solve this customer’s problem: I have a regular […]<\/p>\n","protected":false},"author":1069,"featured_media":111744,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[1],"tags":[25],"class_list":["post-43803","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-oldnewthing","tag-code"],"acf":[],"blog_post_summary":"
Before you ask a question about regular expressions, you should make sure you and your audience agree on which regular expression language you are talking about. Here is a handy table of which features are supported by which regular expression language. You can use that table to solve this customer’s problem: I have a regular […]<\/p>\n","_links":{"self":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/43803","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/users\/1069"}],"replies":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/comments?post=43803"}],"version-history":[{"count":0,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/posts\/43803\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media\/111744"}],"wp:attachment":[{"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/media?parent=43803"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/categories?post=43803"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/devblogs.microsoft.com\/oldnewthing\/wp-json\/wp\/v2\/tags?post=43803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}