The function substr_replace() that replaces part of a php string with another string

Example

Replace "Hello" with "world":

<?php
echo substr_replace("Hello","world",0);
?>

Definition and usage

substr_replace() function replaces the string Replace part of it with another string.

Note: If the start parameter is negative and length is less than or equal to start, length is 0.

Note: This function is binary safe.

Syntax

substr_replace(string,replacement,start,length)

Parameters	Description
string	Required. Specifies the string to check.
replacement	Required. Specifies the string to be inserted.
start	Required. Specifies where in the string to begin replacement. Positive number - starts at the specified position in the string Negative number - starts at the specified position from the end of the string 0 - Starts at the first character in the string
length	Optional. Specifies how many characters to replace. The default is the same as the string length. Positive number - the length of the string to be replaced Negative number - the number of characters to be replaced from the end of the string 0 - Insert instead of replace

Technical details

As of PHP 4.3.3, all parameters accept arrays.

更多实例

实例 1

从字符串的第 6 个位置开始替换（把 "world" 替换成 "earth"）：

<?php
echo substr_replace("Hello world","earth",6);
?>

实例 2

从字符串结尾的第 5 个位置开始替换（把 "world" 替换成 "earth"）：

<?php
echo substr_replace("Hello world","earth",-5);
?>

实例 3

在 "world" 开头插入 "Hello"：

<?php
echo substr_replace("world","Hello ",0,0);
?>

实例 4

一次性替换多个字符串。把每个字符串中的 "AAA" 替换成 "BBB"：

<?php
$replace = array("1: AAA","2: AAA","3: AAA");
echo implode("<br>",substr_replace($replace,&#39;BBB&#39;,3,3));
?>

例子：

<?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 
?>

Return value:	Return the replaced string. If string is an array, the array is returned.
PHP Version:	4+
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