Master PHP’s str_replace(): From Basics to Advanced Tricks

In PHP programming, handling strings often requires replacing characters or substrings. The native str_replace() function is widely used for this purpose.

str_replace() function

The str_replace() function replaces specified characters or substrings in a string. Its syntax is: str_replace($search, $replace, $subject); Here $search is the value to be replaced, $replace is the replacement, and $subject is the original string. Both $search and $replace can be strings or arrays, enabling more complex usage.

Basic usage of str_replace()

Example:

<?php
$str = "php就是如此的美妙！";
$new_str = str_replace("美妙", "优美", $str);
echo $new_str; // 输出：“php就是如此的优美！”
?>

This replaces “美妙” with “优美” in the original string.

Advanced usage of str_replace()

1. Replacing multiple characters or substrings

You can pass arrays to $search and $replace:

<?php
$str = "PHP是一种很不错的语言，值得学习！";
$search = array("PHP", "值得", "！");
$replace = array("php", "很值得", ".");
$new_str = str_replace($search, $replace, $str);
echo $new_str; // 输出：“php是一种很不错的语言，很值得学习.”
?>

This replaces each element of the search array with the corresponding element in the replace array.

2. Case-sensitive replacement

To perform a case‑insensitive replacement, use str_ireplace():

<?php
$str = "PHP是一种很不错的语言，值得学习！";
$new_str = str_ireplace("php", "JAVA", $str);
echo $new_str; // 输出：“JAVA是一种很不错的语言，值得学习！”
?>

3. Getting the number of replacements

The fourth parameter of str_replace() returns the count of replacements performed:

<?php
$str = "PHP是一种很不错的语言，值得学习！";
$new_str = str_replace("PHP", "JAVA", $str, $count);
echo $new_str . " 替换了" . $count . "次"; // 输出：“JAVA是一种很不错的语言，值得学习！替换了1次”
?>

After execution, $count holds the number of replacements.

The str_replace() function is a flexible PHP string function that can handle single or multiple replacements, case sensitivity, and return the number of replacements.