Special characters in regular expressions
Character implication
\ As a turn, that is, the characters usually after "\" are not interpreted in the original sense, such as the/b/matching character "B", when B is preceded by a backslash/\b/, to
1 overviewThis may be a confusing, even confusing topic, but that is why the discussion is necessary.
In regular, some characters that have special meaning, or sequences of characters, are called Meta characters, such as "?" Indicates that the
The escape character in the Java language and the expression of the escape character in the regular syntax in the Java string.There are 14 escape characters in ASCLL:
\o
Null character (NULL)
00h/0
\ n
Line
The checksum is all made up of numbers
Funtin Isigit (s) {var patrn=/^[0-9]{1,20}$/; if (!patrn.x (s)) Rturn Fals Rturn Tru}
Javasript Form validation mail to determine whether an input is mailbox mail and implemented through regular expressions.
Replace () is a simple replacement of characters.
ExampleCodeAs follows:
It only replaces the first letter. However, if you add a regular expression, the results will be different! Replace () supports regular expressions. It can match
The regular expression of JSWhether the checksum is all made up of numbersCodefunction IsDigit (s){var patrn=/^[0-9]{1,20}$/;if (!patrn.exec (s)) return falsereturn True}Check login name: Only 5-20 entries begin with a letter, can be numbered, "_", "
// Check whether it is composed of digits[Code] function isDigit (s) {var patrn =/^ [0-9] {1, 20} $/; if(! Patrn.exe c (s) return false return true} [/code]
// Check Logon Name: You can enter only 5-20 strings starting with a letter, which can
JavaScript's RegExp objects and string objects define methods that use regular expressions to perform powerful pattern matching and text retrieval and substitution functions.
In JavaScript, regular expressions are represented by a RegExp object. Of
The regular expression is a regular expression. It seems that English is better understood than Chinese, that is, the regular expression is checked for non-conforming characters !! Regular expressions have a powerful and complex object RegExp, which
PHP Regular Expression full manual, regular expression full manual
Full Manual of regular expressions for PHP
Objective
Regular expressions are cumbersome, but powerful, learned applications will give you an absolute sense of accomplishment in
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