strlen() Function in PHP

The strlen() function in PHP is a built-in function that is used to return the length of a string. The syntax for the strlen() function is as follows:

strlen(string $string): int

The strlen() function takes a string as input and returns an integer value that represents the number of characters in the string. If the input string is empty, strlen() returns 0.

Here's an example code that demonstrates the use of strlen():

<?php
   $string = "Hello, world!";
   $length = strlen($string);
   echo "The length of the string '$string' is $length.";
?>

The output of the above code will be:

The length of the string 'Hello, world!' is 13.

In this example, we first declare a string variable called $string and assign it the value "Hello, world!". We then use the strlen() function to determine the length of the string and store the result in a variable called $length. Finally, we print out a message that displays the original string and its length using the echo statement.

It's important to note that strlen() only returns the number of characters in a string, not the number of bytes. If your string contains multibyte characters, such as those used in certain languages like Chinese or Japanese, strlen() may not return the expected result. In such cases, you should use the mb_strlen() function instead, which is specifically designed to handle multibyte characters.