PHP:
Finding the length of a string
How to:
Use the strlen() function like this:
<?php
$text = "Hello, world!";
$length = strlen($text);
echo $length; // Output: 13
?>
If you run this, you’ll see 13 on your screen because “Hello, world!” is 13 characters long, including the space and exclamation point.
Deep Dive
The strlen() function has been part of PHP since the early versions. It’s straightforward and works based on the number of bytes, which is usually equivalent to the number of characters in strings without special encoding considerations.
However, with the internationalization of web applications, dealing with multiple languages and character encodings became usual. Characters in UTF-8, for instance, can use more than one byte. That’s where mb_strlen() comes in:
<?php
// A string with multibyte characters
$multibyteText = "こんにちは";
$length = mb_strlen($multibyteText, "UTF-8");
echo $length; // Output: 5
?>
Five characters, but more bytes. The mb_strlen() function respects character encoding, ensuring accurate length checks for multibyte strings.
strlen() is fast and suitable for single-byte character sets. mb_strlen(), while slightly slower due to its need to handle more complex encoding, is necessary when working with internationalized text.