Handling Unicode and UTF-8 Strings

When you need to work with UTF-8 without slicing through multibyte characters, it helps to understand both the normal result and what changes with different inputs. This guide focuses on practical examples rather than repeating PHP background material.

Handling Unicode and UTF-8 Strings provides the behavior described below. strlen() counts bytes; mb_strlen() counts code points; grapheme_strlen() counts displayed grapheme clusters.

What Is Handling Unicode and UTF-8 Strings in PHP?

Work with utf-8 without slicing through multibyte characters. strlen() counts bytes; mb_strlen() counts code points; grapheme_strlen() counts displayed grapheme clusters.

Its syntax is:

mb_strlen($text, "UTF-8")

Parameters and return value: Read the argument names and optional values in the signature above. Methods use an existing object, while stand-alone functions take direct arguments. The examples demonstrate the relevant arguments and the value returned or the object modified.

Important: Always declare the encoding when it matters and check for invalid UTF-8 at input boundaries.

Example 1: Basic Usage

This first example demonstrates how to work with UTF-8 without slicing through multibyte characters with a small input.

<?php

$text = "café";
echo strlen($text);

The example uses the simplest useful form. strlen() counts bytes; mb_strlen() counts code points; grapheme_strlen() counts displayed grapheme clusters. The output may depend on the active ICU locale, PHP configuration, or input supplied to the function.

Example 2: Another Case

Here the input or option changes, making it easier to see where the behavior differs. Always declare the encoding when it matters and check for invalid UTF-8 at input boundaries.

<?php

$text = "café";
echo mb_strlen($text, "UTF-8");

Compare the result to the first example. Use mb_substr for code points and grapheme_substr for user-visible grapheme sequences.

Practical Example: Applying the Function

This standalone example shows how the same operation fits into a small application task. The intl extension is required for this example.

<?php

$caption = "Hello 🌍";
echo "Bytes: " . strlen($caption) . PHP_EOL;
echo "Characters: " . mb_strlen($caption, "UTF-8");

The example keeps the operation visible and gives you a starting point for using it in an application. Always declare the encoding when it matters and check for invalid UTF-8 at input boundaries.

Important Behavior and Edge Cases

• Core behavior: strlen() counts bytes; mb_strlen() counts code points; grapheme_strlen() counts displayed grapheme clusters.
• Return value: Check the result separately from changes to passed-in arrays, iterators, or object state.
• Data constraints: Always declare the encoding when it matters and check for invalid UTF-8 at input boundaries.
• Environment: The intl extension is required for this example.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• Handling Unicode and UTF-8 Strings helps you work with UTF-8 without slicing through multibyte characters.
• strlen() counts bytes; mb_strlen() counts code points; grapheme_strlen() counts displayed grapheme clusters.
• Always declare the encoding when it matters and check for invalid UTF-8 at input boundaries.
• Use mb_substr for code points and grapheme_substr for user-visible grapheme sequences.

Handling Unicode and UTF-8 Strings is useful when you need to work with UTF-8 without slicing through multibyte characters. Start with the small examples, then adapt the practical example while respecting its input and environment requirements.