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What are the functions of regular expressions in JavaScript? In view of this problem, this article introduces the corresponding analysis and answers in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible way.

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Creation of regular expressions

Special characters in regular expressions

\ (backslash)

^

$

*, +,. (decimal point)

? (question mark)

(x)

(X)

X (? = y), x (?! y), x | y

{n}, {n,m}:

[xyz], [^ xyz]

Other

Regular expression flag

Regular expressions use the

Most of the time, I will be confused by regular expressions. Recently, I have taken the time to study regular expressions systematically, as follows:

Creation of regular expressions

There are two ways, one is to write directly, which consists of patterns contained between slashes, and the other is to call the constructor of the RegExp object.

The creation code for the two methods is as follows:

/ / directly create const regex1 = / ab+c/;const regex2 = / ^ [a-zA-Z] + [0-9] *\ Wholeships. / call the constructor const regex3 = new RegExp ('ab+c'); const regex4 = new RegExp (/ ^ [a-zA-Z] + [0-9] *\ Whampodash, "gi"); const regex5 = new RegExp (' ^ [a-zA-Z] + [0-9] *\ Wholeships, 'gi')

As you can see, when you call the RegExp constructor to create a regular expression, the first parameter can be a string or a regular expression created directly.

It should be noted that both the toLocaleString () and toString) () methods inherited by the RegExp instance return the literal amount of the regular expression, regardless of how the regular expression is created.

For example:

Const ncname ='[a ncname ZZ] [\\ w\ -\\] *'; const qnameCapture ='((?:'+ ncname +'\:)?'+ ncname +')'; const startTagOpen = new RegExp ('^

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