How do you replace specific characters in a PHP string?

In PHP, you can use the str_replace() function to replace specific characters in a string. This function takes in three parameters: the character or array of characters to be replaced, the character or array of characters to replace them with, and the string in which the replacement operation will be performed.

The sample code is as follows:

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

In the example above, we replaced “World” in the string with “PHP” and stored the updated result in the $newStr variable. We then used the echo statement to output the new string on the screen.