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js uses regular expressions to implement ReplaceAll replacement method_javascript skills

WBOYOriginal: 2016-05-16 16:39:052338browse

JS strings have the replace() method. But this method will only replace the first matched string. For example:

<HTML>
<HEAD>
<TITLE> New Document </TITLE>
</HEAD>

<BODY>
<script>
var str = "wordwordwordword";
var strNew = str.replace("word","Excel");
alert(strNew);
</script>
</BODY>
</HTML>

If you want to replace all, JS does not provide a method like replaceAll. The effect of Replace can be achieved using regular tables:

str.replace(/word/g,"Excel")

g means: perform a global match (find all matches instead of stopping after the first match is found).

<HEAD>
<TITLE> New Document </TITLE>
<script>
function replaceAll(str)
{
if(str!=null)
str = str.replace(/word/g,"Excel")
return str;
}
</script>
</HEAD>

<BODY>
<script>
var str = "wordwordwordword";
var strNew = str.replace("word","Excel");
strNew = replaceAll(str);
alert(strNew);
</script>
</BODY>
</HTML>

The above writing method has a similar writing method:

str.replace(new RegExp("word","gm"),"Excel")

g performs a global match (finds all matches instead of stopping after the first match is found).

m performs multi-line matching.

In addition, you can also add the prototype method of the Stirng object:

String.prototype.replaceAll = function(s1,s2){ 
return this.replace(new RegExp(s1,"gm"),s2); 
}

This way you can use replaceAll just like using the replace method

str.replaceAll("word","Excel");

To summarize, there are three ways

1. str.replace(/oldString/g,newString)

2. str.replace(new RegExp(oldString,"gm"),newString)

3. Add String object prototype method replaceAll

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