In-depth understanding of the Replace method in JavaScript (GO)

The Replace method is a string object and can be used to replace strings.

Brief introduction:

Stringobject.replace (Searchvalue,replacevalue)

1. Stringobject: String
2. Searchvalue: string or Regular expression
3. Replacevalue: String or function

String substitution string

JavaScript

1	' I am loser! ' . Replace(' loser ',' hero ')//i am hero!

The use of strings directly allows you to change from loser to hero, but if you have 2 loser you can't turn hero together.

JavaScript

1	' I am loser,you is loser '. Replace(' loser ',' hero '); I am Hero,you is loser

The regular expression is replaced with a string

JavaScript

1	' I am loser,you is loser '. Replace(/loser/g,' hero ')//i am hero,you are hero

Use regular expressions and change the regular global property to True to make all loser become hero

Interesting substitution characters

Replacevalue can be a string. If there are several specific characters in the string, it is converted to a specific string.

Character	Replace text
$&	A string that matches a regular match
$	Match the character to the left of the string
$	Match the character to the right of the string
$1,$2,$,3,..., $n	Matching results for the corresponding grouped matches

Use $& characters to add parentheses to matching characters

JavaScript

12	var sStr=' discusses the use of Replace in regular expressions '; sStr. Replace(/Regular expression /,' {$&} '); Discuss the use of Replace in {regular expression}

Replace content with $ and $ ' characters

JavaScript

12	' abc '. Replace(/b/,"$ '"); AAC' abc '. Replace(/b/,"$ '"); ACC

Combine new strings with grouping matches

JavaScript

1	' [email protected] '. Replace(/(. +)(@)(. *)/,"$2$1")//@nimojs

The Replacevalue parameter can be a function

The replacevalue in Stringobject.replace (Searchvalue,replacevalue) can be a function.
If Replacevalue is a function, then the arguments of this function will have n+3 parameters (the number of times that n matches the regular match)
First look at examples to help understand:

JavaScript

1234567

function logarguments(){ console. Log(arguments); ["[Email protected]", "Nimojs", "@", "126.com", 0, "[email protected]"] return ' returned value will replace match to target ' }console. Log( ' [email protected] '. Replace(/(. +)(@)(. *)/,logarguments) )

Parameters are

1. Match to the string (this example is [email protected], it is recommended to modify the above code of the regular to see the matching characters to help understand)
2. If the regular uses a grouping match for more than one otherwise there is no this parameter. (The parameters for this example are "Nimojs", "@", "126.com", respectively.) Recommended modification Regular is/nimo/view the arguments value returned in console)
3. Match the corresponding index position of the string (this example is 0)
4. Raw string (This example is [email protected])

Use a custom function to change the a-g string to lowercase

JavaScript

123	' JAVASCRIPT ' . Replace/[a-g]/gfunction ({      return arguments[ 0]. Tolowercase }) //javascript

Use a custom function to make a callback replace the single quotation mark in the inline style

JavaScript

1234567

' <span style= ' font-family:\ ' Microsoft Ya Black '; >demo</span> '. Replace(/\ ' [^ ']+\ '/g,function(){ var sresult=arguments[0]; console. Log(sresult); ' Microsoft Ya Black ' Sresult=sresult. Replace(/\ '/g,'); console. Log(sresult); Microsoft Ya-Black return sresult; })//<span style= "font-family: Microsoft Jacob Black;" >demo</span>

The last little trial sledgehammer

This section is for the reader to play the content:

1. Using functions to implement substitution characters autonomously

Character	Replace text
$&	A string that matches a regular match
$`	Match the character to the left of the string
$	Match the character to the right of the string

Use regular but not using the substitution character method above to implement three instances of interesting substitution characters .

2. Wash poker

Need to replace thisnimojs-javascript with a T-JhaivsaNsicmr oiJpst

Original link: http://www.nimojs.com/blog/javascript-replace/

In-depth understanding of the Replace method in JavaScript (go)