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
Introduction
A regular expression (Regular Expression) describes a feature using a "string", and then verifies whether another "string" matches this feature. For example, if the expression "AB +" describes the features of "a" and any 'B' ", 'AB',
Introduction
A regular expression (Regular Expression) describes a feature using a "string", and then verifies whether another "string" matches this feature. For example, if the expression "AB +" describes the features of "a" and any 'B' ", 'AB',
1. Regular Expression rules 1.1 common characters
Letters, numbers, Chinese characters, underscores, and punctuation marks not defined in the subsequent sections are all "common characters ". A common character in an expression. It matches the same
Introduction
The regular expression describes a string matching mode. It can be used to: (1) check whether a string contains a child string that complies with a specific rule and obtain the child string; (2) flexibly replace strings according to
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, "_", "
Regular Expression of QT
The qregexp class under the qtcore component of QT provides good support for regular expression.
First, what is a regular expression? For example, if you want to find the person surnamed 'King' from a sentence text, you
// 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
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
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