Using PHP str_replace for String Replacement and Deletion

In PHP, strings are a common data type and the built‑in str_replace function provides a simple way to replace or delete characters within a string.

The syntax is str_replace($search, $replace, $subject); where the function searches the $subject for $search and replaces each occurrence with $replace .

Example 1 – Simple replacement

$text = "今天是星期一，明天是星期二，后天是星期三。";
$new_text = str_replace("星期一", "周一", $text);
echo $new_text;

Output: 今天是周一，明天是星期二，后天是星期三。

Example 2 – Replacing multiple substrings

$text = "The quick brown fox jumps over the lazy dog.";
$new_text = str_replace(array("quick", "brown", "lazy"), "slow", $text);
echo $new_text;

Output: The slow fox jumps over the slow dog.

Example 3 – Deleting characters

$text = "Hello, world!";
$new_text = str_replace("o", "", $text);
echo $new_text;

Output: Hell, wrld!

The function also supports optional parameters such as limiting the number of replacements or performing case‑sensitive searches, which are documented in the official PHP manual.

In summary, str_replace is a versatile and efficient tool for string manipulation in PHP, allowing developers to replace or remove specific characters or substrings with minimal code.