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Xiaobian to share with you what are practical regular expressions, I believe that most people do not know much about it, so share this article for your reference, I hope you can learn a lot after reading this article, let's learn about it!

Regular expressions are very useful, finding, matching, manipulating strings, replacing and converting strings, input and output, and so on. And various languages support, such as. Net regular library, JDK regular package, Perl, JavaScript and other scripting languages all support regular expressions.

Character

Description

\ Mark the next character as a special character, or a literal character, or a backward reference, or an octal escape character. For example,'n 'matches the character "n".' \ n' matches a newline character. The sequence'\ 'matches "\" and "(" matches "(". ^ matches the starting position of the input string. If the Multiline property of the RegExp object is set, ^ also matches the position after'\ n'or'\ r'. $matches the end of the input string. If the Multiline property of the RegExp object is set, $also matches the position before'\ n'or'\ r'. * matches the previous subexpression zero or more times. For example, zo* can match "z" and "zoo". * is equivalent to {0,}. + matches the previous subexpression one or more times. For example, 'zo+' can match "zo" and "zoo", but not "z". + is equivalent to {1,}. ? Matches the previous subexpression zero or once. For example, "do (es)?" Can match "do" in "do" or "does". ? It is equivalent to {0jue 1}. {n} n is a non-negative integer. Match the determined n times. For example,'o {2} 'does not match the' o'in 'Bob', but does match the two o in 'food'. {n,} n is a non-negative integer. Match at least n times. For example,'o {2,} 'does not match' o'in 'Bob', but does match all o in 'foooood'. O {1,}'is equivalent to 'oasis'. O {0,}'is equivalent to 'oval'. {n ·m} m} m and n are non-negative integers, where n

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