![]() Let's use this pattern inside a lookahead: The lookahead asserts: at this position in the string (i.e., the beginning of the string), we can match. You're just looking, not moving look aheadLet's start with condition 1\A anchor \z anchor \A\ACondition 2. NET you could use RegexOptions.Singleline for this. A regular expression (shortened as regex or regexp sometimes referred to as rational expression) is a sequence of characters that specifies a match pattern in text.Usually such patterns are used by string-searching algorithms for 'find' or 'find and replace' operations on strings, or for input validation. three uppercase characters A-Z With lookarounds, your feet stay planted on the string. You should use regex option dot matches newline (if supported). Of course, this is still not what you want if you need to cope with in it" src="other attributes"> and perhaps, but at that point, you should finally give up on using regular expressions for this like we all told you in the first place. In regex you should use the \r to catch the carriage return and \r to catch the line breaks. *?> will jump over any nested > until it finds the trailing context (here, >) even if that requires straddling multiple > instances and newlines if you let it, where *> (or even *> if you have to explicitly disallow newline) obviously can't and won't do that. If this is what you mean, you should probably say this, instead of rely on non-greedy matching to (hopefully, probably) Do What I Mean.įor example, a regular expression with a trailing context after the wildcard like. ![]() ![]() "any character", but instead "any character which isn't >".ĭepending on your application, you may or may not want to enable an option to permit "any character" to include newlines.Įven if your regular expression engine supports non-greedy matching, it's better to spell out what you actually mean. Which still matches as many of something as possible but the something is not just. The trick then is to limit what it's allowed to match in the first place. Many older or more conservative languages and editors only support traditional regular expressions, which have no mechanism for controlling greediness of the repetition operator * - it always matches the longest possible string. The other answers here presuppose that you have a regex engine which supports non-greedy matching, which is an extension introduced in Perl 5 and widely copied to other modern languages but it is by no means ubiquitous.
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