From MSDN: By default, $ matches only the end of the input string. If you specify the RegexOptions.Multiline option, it matches either the newline character (\n) or the end of the input string. It does not, however, match the carriage return/line feed character combination. To successfully match them, use the subexpression \r?$ instead of just … Read more
You can achieve this will lookahead assertions ^(?=.*\bmeat\b)(?=.*\bpasta\b)(?=.*\bdinner\b).+ See it here on Regexr (?=.*\bmeat\b) is a positive lookahead assertion, that ensures that \bmeat\b is somewhere in the string. Same for the other keywords and the .+ is then actually matching the whole string, but only if the assertions are true. But it will match also … Read more
Subdomain According to the pertinent internet recommendations (RFC3986 section 2.2, which in turn refers to: RFC1034 section 3.5 and RFC1123 section 2.1), a subdomain (which is a part of a DNS domain host name), must meet several requirements: Each subdomain part must have a length no greater than 63. Each subdomain part must begin and … Read more
The slashes indicate the start and end of the regular expression. The g at the end is a flag and indicates it is a global search. From the docs: Regular expressions have four optional flags that allow for global and case insensitive searching. To indicate a global search, use the g flag. To indicate a … Read more
Firstly the tricky part in your question is the first line in the .gitignore file: * // Says exclude each and every file in the repository, // unless I specify with ! pattern explicitly to consider it First we will consider the first version of your .gitignore. * exclude every file in the repository. !*.html … Read more
You can put a ? after a group of characters to make it optional. You want a dot followed by any number of digits \.\d+, grouped together (\.\d+), optionally (\.\d+)?. Stick that in your pattern: import re print re.match(“(\d+(\.\d+)?)”, “3434.35353”).group(1) 3434.35353 print re.match(“(\d+(\.\d+)?)”, “3434”).group(1) 3434
Don’t use a regex when you don’t need to 🙂 $valid = filter_var($string, FILTER_VALIDATE_IP); Though if you really do want a regex… $valid = preg_match(‘/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\z/’, $string); The regex however will only validate the format, the max for any octet is the max for an unsigned byte, or 255. This is why IPv6 is necessary – … Read more
Use Regexp.union to combine them: union(pats_ary) → new_regexp Return a Regexp object that is the union of the given patterns, i.e., will match any of its parts. So this will do: re = Regexp.union(prefixes) then you use re as your regex: if name.match(re) #…
Okay, I have refined my regular expression based on the solution you came up with (which erroneously matches strings that start with ‘test’). ^((?!foo).)*$ This regular expression will match only strings that do not contain foo. The first lookahead will deny strings beginning with ‘foo’, and the second will make sure that foo isn’t found … Read more
There is some catastrophic backtracking going on that will cause an exponential amount of processing depending on how long the non-match string is. This has to do with your nested repetitions and optional comma (even though some regex engines can determine that this wouldn’t be a match with attempting all of the extraneous repetition). This … Read more