The preg_replace operator can be used to replace values in a string. For example, let's say you have a variable that contains the text Hello World.
$string = "Hello World";
In this example, the word "Hello" is replaced with "Goodbye".
$string = preg_replace('/Hello/', 'Goodbye', $string);
Now, when you echo $string . . .
. . . the following will be displayed.
Or, you could use a regular expression in the replacement.
$string = preg_replace('/^[A-Z]ello /', 'Goodbye', $string);
It is common to define variables for the values being used in preg_replace, like this.
$string = "Hello World"; $regex = '/^[A-Z]ello /'; $replacement = "Goodbye"; $string = preg_replace($regex, $replacement, $string);