How to replace a string at a specified position in php

In PHP, you can use the str_replace() function to replace a string at a specified position. The syntax format is "substr_replace(string,replacement,start,length)". The parameter start is used to specify the replacement position (in the string where to start the replacement).

The operating environment of this tutorial: windows7 system, PHP7.1 version, DELL G3 computer

php replaces the specified location string

<?php
$str = &#39;hello world&#39;;
// 替换指定位置的字符
$str = substr_replace($str,"earth",6);;
// 显示字符
echo $str;
?>

Output:

hello earth

Related function description:

substr_replace() function replaces part of a string with another string. The syntax is as follows:

substr_replace(string,replacement,start,length)

##ParameterDescriptionRequired. Specifies the string to check. Required. Specifies the string to be inserted. Required. Specifies where in the string to begin replacement. Optional. Specifies how many characters to replace. The default is the same as the string length.

string
replacement
start	Positive number - starts at the specified position in the string Negative number - starts at the specified position from the end of the string 0 - at the first character in the string Start at
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

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

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