How to perform string replacement in php

String replacement method: 1. Use the str_replace() function, the syntax "str_replace(search value, replacement value, string)"; 2. Use the substr_replace() function, the syntax "substr_replace(string, replace value, starting position, replacement length)".

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

In PHP, you can edit a string Replace specific characters or substrings, which is a very common function.

php string replacement

Method 1: str_ireplace() and str_replace() functions

str_ireplace() and str_replace use a new string to replace a specific string specified in the original string. str_replace is case-sensitive, while str_ireplace() is not case-sensitive. The syntax of the two is similar.

str_replace(find,replace,string,count)
str_ireplace(find,replace,string,count)

Parameters	Description
find	Required . Specifies the value to look for.
replace	Required. Specifies a value that replaces the value in find.
string	Required. Specifies the string to be searched for.
count	Optional. Variable counting the number of substitutions.

Example:

<?php
header("Content-type:text/html;charset=utf-8");
$str = &#39;hello,world,Hello,world&#39;;
echo "原字符串：".$str."<br>";

$search = &#39;hello&#39;;
$replace = &#39;hi&#39;;

echo "<br>替换字符串：<br>";
echo str_replace($search, $replace, $str)."<br>";
echo str_ireplace($search, $replace, $str)."<br>";
?>

Method 2: substr_replace() function

substr_replace() function replaces part of a string with another string.

The syntax of the substr_replace() function is as follows:

substr_replace(string,replacement,start,length)

##ParametersDescriptionRequired. 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

Example:

<?php
$str = &#39;hello,world,hello,world&#39;;
$replace = &#39;hi&#39;;
echo substr_replace($str, $replace, 0,5);
?>

The execution result of the above code is:

hi,world,hello,world

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