Pattern matching methods in String objects

directory

1. The match () method

Grammar: stringobj. Match (rgExp)

Example:

2. The search () method

Grammar: stringobj. Search (rgExp)

Example:

3. The replace () method

Grammar: replace (rgExp replaceText)

Example:

4. The split () method

Grammar: the split ([the separator [limit]])

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1. The match () method

The match () method uses the regular expression pattern to find the string and returns the results containing the lookup as an array.

Grammar: stringobj. Match (rgExp)

Stringobj: Mandatory. The String or String literal on which to look up

RgExp: Mandatory. Regular expression objects for regular expression patterns and available flags. It can also be a variable name or string literal that contains regular expression patterns and available flags.

If the match method does not find a match, null is returned. If a match is found, an array is returned and the properties of the global RegExp object are updated to reflect the result.

The match method returns an array with three attributes: input, index, and lastIndex.

If there is no global flag (g), element 0 of the array contains the entire match, and elements 1-n contain any child matches that have ever occurred in the match. This is equivalent to no global flag being set, and elements 0-n contain all matches.

Example:

        <script language="JavaScript">
			function MatchDemo(){
				var r,re;         // Declare variables
				var s="I'm a good man"; 
				re=/man/i;       // Create a regular expression
				r=s.match(re);    // Try to match the search string
				return(r);        // Return to the first occurrence of "body"
			}
			document.write(MatchDemo());
		</script>	
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        <script language="JavaScript">
			function MatchDemo(){
				var r,re;         // Declare variables
				var s="I'm a man a good man"; 
				re=/man/ig;       // Create a regular expression
				r=s.match(re);    // Try to match the search string
				return(r);        // Return to the first occurrence of "body"
			}
			document.write(MatchDemo());
		</script>	
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2. The search () method

The search() method returns the position of the first substring that matches the regular expression lookup.

Grammar: stringobj. Search (rgExp)

Stringobj: Mandatory. The String or String literal on which to look up

RgExp: Mandatory. Regular expression objects for regular expression patterns and available flags. It can also be a variable name or string literal that contains regular expression patterns and available flags.

Example:

            <script language="JavaScript">
			function MatchDemo(){
				var r,re;         // Declare variables
				var s="I'm a man a good man"; 
				re=/man/ig;       // Create a regular expression
				r=s.search(re);    // Try to match the search string
				return(r);        // Return to the first occurrence of "body"
			}
			document.write(MatchDemo());
		</script>	
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3. The replace () method

The replace() method searches the string using an expression pattern and replaces the searched content with the specified string, returning a string object containing the replaced content.

Grammar: replace (rgExp replaceText)

The rgExp argument is the expression object to use when searching. If it is a string, the search is precise rather than fuzzy as a regular expression.

The replaceText parameter is a string used to replace what was searched, where special character combinations can be used to represent matching variables. Where $& is the string that the entire expression pattern matches in the searched string, $is all the content to the left of the string that the expression pattern matches in the searched string, $’ is all the content to the right of the string that the expression pattern matches in the searched string, and $$is the ordinary meaning of the “$” character.

Example:

        <script language="JavaScript">
			var strSrc="a13f58af4f41af";
			var re=/(\d)(\d)/gi;
			var strDest=strSrc.replace(re,"$2 $1");
			document.write("String"+strSrc+"Is converted to:"+strDest);
		</script>	
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4. The split () method

The split() method returns an array of substrings produced when a string is split into substrings by some split identifier.

Grammar: the split ([the separator [limit]])

Separator is the split identifier argument, which can be multiple characters or a regular expression and is not returned as part of the array element. The limit argument limits the number of elements returned.

            <font size="+ 1"<font face="宋体"> <script language="JavaScript"> var splitArray=new Array(); Var string="JavaScript, ASP, JSP, Java"; Var regex = /, /; splitArray=string.split(regex); for(i=0; i<splitArray.length; i++){ document.write(splitArray[i]+" "); } </script>Copy the code