string php how to replace string

There are two functions in PHP that can replace strings, namely: 1. substr_replace function, which is used to replace part of a string with another string; 2. str_replace function, which Used to replace other characters in a string.

The operating environment of this article: windows7 system, PHP version 7.1, DELL G3 computer

PHP string replacement substr_replace and str_replace functions

PHP String Replacement

Used to replace the specified string from a string.

Relevant functions are as follows:

• substr_replace(): Replace part of a string with another string
• str_replace(): Use a string to replace characters Other characters in the string

substr_replace()

substr_replace() function is used to replace part of the string with another string and return a mixed type.

Syntax:

mix substr_replace ( mixed string, string replacement, int start [, int length] )

Parameter description is as follows:

Parameter	Description
string	String to be processed
replacement	String to be inserted
start	The starting position of the string, the starting position is 0, if it is negative, it starts from the specified position at the end of the string
length	Optional, the length of the string returned, the default is until the end of the string, if it is negative, it will be returned from the end of the string

Example:

<?php
echo substr_replace(&#39;abcdef&#39;, &#39;###&#39;, 1);	//输出 a###
echo substr_replace(&#39;abcdef&#39;, &#39;###&#39;, 1, 2);	//输出 a###def
echo substr_replace(&#39;abcdef&#39;, &#39;###&#39;, -3, 2);	//输出 abc###f
echo substr_replace(&#39;abcdef&#39;, &#39;###&#39;, 1, -2);	//输出 a###ef 
?>

Tip

If start is a negative number and length is less than or equal to start, length is 0.

str_replace()

str_replace() function uses a string to replace other characters in the string and returns a mixed type. [Recommended learning: PHP video tutorial]

Syntax:

mixed str_replace( mixed search, mixed replace, mixed string [, int &count] )

The parameter description is as follows:

Parameter	Description
search	The string to be found (replaced)
replace	String to replace search
string	String to be processed
count	Optional, a variable that counts substitutions

Example:

<?php
echo str_replace("world","earth","Hello world!");		//输出 Hello earth!
//替换多个，且第二个参数为空字符
echo str_replace("o","","Hello world!");			//输出 Hell wrld! 
//使用数组
$arr = array("e", "o");
$arr2 = array("x", "y");
echo str_replace($arr, $arr2, "Hello World of PHP", $i);	//输出 Hxlly Wyrld yf PHP 
echo $i;							//输出4  
?>

Tips

1. This function is the same as substr_replace( ) The difference is that all those that meet the conditions are replaced
2. This function is case-sensitive. For case-insensitive search and replace, use str_ireplace()

The above is the detailed content of string php how to replace string. For more information, please follow other related articles on the PHP Chinese website!