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What are the ways to use regular expressions in javascript?

青灯夜游

Jan 12, 2022 pm 04:45 PM

javascriptregular

Regular methods in JavaScript: 1. exec(), used to retrieve matches of regular expressions in strings; 2. test(), used to detect whether a string matches a specified regular expression; 3. toString(); 4. replace(); 5. match(); 6. search().

What are the ways to use regular expressions in javascript?

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

What is regular expression

Regular expression is an object that describes a character pattern.

Regular expressions are used to match string patterns and retrieve and replace them. They are a powerful tool for performing pattern matching on strings.

RegExp Object Method

Method	Description
compile	is deprecated in version 1.5. Compile regular expressions.
exec	Retrieve the value specified in the string. Returns the found value and determines its position.
test	Retrieve the value specified in the string. Returns true or false.
toString	Returns the string of the regular expression.

Methods of String objects that support regular expressions

Methods	Description	FF	IE
search	Retrieve values that match a regular expression.	1	4
match	Find a match for one or more regular expressions.	1	4
replace	Replace the substring that matches the regular expression.	1	4
split	Split the string into a string array.	1	4

JavaScript exec() method

exec() method Used to retrieve matches of a regular expression in a string.

If there is a matching value in the string, return the matching value, otherwise return null.

var str="Hello world!";
//查找"Hello"
var patt=/Hello/g;
var result=patt.exec(str);
document.write("返回值: " +  result); 
//查找 "php"
patt=/php/g;
result=patt.exec(str);
document.write("<br>返回值: " +  result);

What are the ways to use regular expressions in javascript?

JavaScript test() method

The test() method is used to test whether a string matches a certain pattern.

Returns true if there is a matching value in the string, otherwise returns false.

var str="Hello world!";
//查找"Hello"
var patt=/Hello/g;
var result=patt.test(str);
document.write("返回值: " +  result); 
//查找 "php"
patt=/php/g;
result=patt.test(str);
document.write("<br>返回值: " +  result);

What are the ways to use regular expressions in javascript?

JavaScript RegExp toString() method

toString() method returns the string value of a regular expression.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>

<p>点击按钮返回正则表达式的字符串值。</p>

<button onclick="myFunction()">点我</button>
	
<p id="demo"></p>
	
<script>
function myFunction() {
    var patt = new RegExp("PHP中文网", "g");
    var res = patt.toString();
    document.getElementById("demo").innerHTML = res;
}
</script>

</body>
</html>

What are the ways to use regular expressions in javascript?

JavaScript replace() method

replace() method is used to replace some characters with other characters in a string , or replace a substring that matches a regular expression.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>

<p>单击按钮将段落中的“blue”替换成“red”。</p>
<p id="demo">Mr Blue has a blue house and a blue car.</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
	var str=document.getElementById("demo").innerHTML; 
	var n=str.replace(/blue/gi,"red");
	document.getElementById("demo").innerHTML=n;
}
</script>

</body>
</html>

What are the ways to use regular expressions in javascript?

JavaScript match() method

The match() method retrieves a specified value within a string, or finds a or multiple regular expression matches.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>

<p id="demo">单击按钮显示matches</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
	var str="The rain in SPAIN stays mainly in the plain"; 
	var n=str.match(/ain/g);
	document.getElementById("demo").innerHTML=n;
}
</script>

</body>
</html>

What are the ways to use regular expressions in javascript?

JavaScript search() method

The search() method is used to retrieve a specified substring in a string, or Retrieve substrings that match a regular expression.

If no matching substring is found, -1 is returned.

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>

<p id="demo">单击显示查找的位置</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
	var str="Mr. Blue has a blue house"
	var n=str.search("blue");
	document.getElementById("demo").innerHTML=n;
}
</script>

</body>
</html>

What are the ways to use regular expressions in javascript?

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