Using str_replace() in PHP: Syntax, Parameters, and Examples

In PHP, string manipulation is a common task, and the str_replace() function is widely used to replace specific characters or substrings.

The syntax of str_replace() is:

str_replace(search, replace, subject)

Parameter description:

search : the value to be replaced; can be a string or an array.

replace : the replacement value; can be a string or an array (must match the size of search when both are arrays).

subject : the target string on which the replacement is performed.

Return value:

The function returns the string after replacement.

Example 1: Replace a single character

$str = "Hello, World!";
$newStr = str_replace("World", "PHP", $str);
echo $newStr; // Output: Hello, PHP!

This example replaces "World" with "PHP" and prints the result.

Example 2: Replace multiple characters

$str = "Hello, World!";
$search = array("Hello", "World");
$replace = array("Hi", "PHP");
$newStr = str_replace($search, $replace, $str);
echo $newStr; // Output: Hi, PHP!

This example replaces "Hello" with "Hi" and "World" with "PHP".

Example 3: Case‑insensitive replacement

$str = "Hello, world!";
$newStr = str_ireplace("WORLD", "PHP", $str);
echo $newStr; // Output: Hello, PHP!

Using str_ireplace() performs a case‑insensitive replacement.

Conclusion

The str_replace() function is a flexible tool for PHP developers, capable of handling single or multiple replacements and offering case‑insensitive options via str_ireplace() . Mastering it simplifies string operations in backend development.