What is the replacement function in php string

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

#The operating environment of this article: Windows7 system, PHP7.1, Dell G3 computer.

PHP String Replacement

Used to replace the specified string from a string.

Related 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 a string with another string and return a mixed type.

Syntax:

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

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. [Recommended: PHP Video Tutorial]

str_replace()

str_replace() function uses a string to replace other characters in the string and returns a mixed type.

Syntax:

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

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  
?>

Prompt

1. The difference between this function and substr_replace() 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()

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