How to Replace Part of a string with Another String in PHP?

Given a String, the task is to replace the part of a string with another string in PHP. There are several methods to replace part of a string with another string. This operation is useful when you need to modify a string, such as replacing certain characters or substrings.

Approach 1: Using str_replace() Function

The str_replace() function is a built-in PHP function that replaces all occurrences of a search string with a replacement string in a given string.

<?php

$str = "Welcome to GeeksforGeeks - Computer Science Portal";
$newStr = str_replace("GeeksforGeeks - Computer Science Porta", "GeeksforGeeks", $str);

echo "New String: $newStr";

?>

New String: Welcome to GeeksforGeeksl

Explanation:

• The str_replace() function takes three arguments: the search string, the replacement string, and the input string. It replaces all occurrences of the search string with the replacement string in the input string.

Approach 2: Using substr_replace() Function

The substr_replace() function replaces a portion of a string with another string.

<?php

$str = "Welcome to GeeksforGeeks - Computer Science Portal";

$newStr = substr_replace($str, "GeeksforGeeks", 11, 50);

echo "New String: $newStr";

?>

New String: Welcome to GeeksforGeeks

Explanation:

The substr_replace() function takes four arguments: the input string, the replacement string, the start position of the replacement, and the length of the portion to be replaced.

Approach 3: Using Regular Expressions

Regular expressions can also be used to replace part of a string with another string.

<?php

$str = "Welcome to GeeksforGeeks - Computer Science Portal";

$newStr = preg_replace("/GeeksforGeeks - Computer Science Portal/", "GeeksforGeeks", $str);

echo "New String: $newStr";

?>

New String: Welcome to GeeksforGeeks

Explanation:

The preg_replace() function performs a regular expression search and replace. It takes three arguments: the regular expression pattern, the replacement string, and the input string.

Approach 4: Using strtr() Function

The strtr() function in PHP is used to translate certain characters or replace substrings in a string. It can replace multiple characters or substrings simultaneously.

Example: In this example, the strtr() function takes two arguments: the input string and an associative array where the keys are the substrings to be replaced and the values are the corresponding replacements.

<?php
// Sample string
$string = "Hello, world!";

// Define the replacements
$replacements = array("Hello" => "Hi", "world" => "earth");

// Replace parts of the string
$result = strtr($string, $replacements);

echo $result;
?>

Hi, earth!