Should I use `mb_strlen($text, 'utf-8')` or `strlen($text)` in PHP ?

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In most cases, you should use mb_strlen($text, 'utf-8') in PHP. Here’s a breakdown of the reasons:

  • Accuracy for Multibyte Characters: mb_strlen is designed for handling multibyte character encodings like UTF-8. It considers characters that can be composed of multiple bytes, giving you the correct character count. strlen assumes single-byte characters and might undercount the length for strings with characters outside the basic ASCII range.

  • Consistency: If you’re working with UTF-8 encoded data (which is very common these days), using mb_strlen ensures consistency throughout your code. It avoids unexpected behavior when encountering non-ASCII characters.

  • Future-proofing: Even if your current data primarily uses ASCII characters, using mb_strlen prepares your code for potential future scenarios where you might handle text in other encodings.

When to use strlen? ๐Ÿ”—

There might be a few rare cases where strlen is acceptable:

  • Legacy Code: If you’re working with very old code that specifically relies on byte-based string lengths and you’re certain the data uses only single-byte characters (ASCII), strlen might be okay. However, even in such cases, consider the future maintainability and potential for data changes.

  • Byte-Specific Operations: If you explicitly need the byte length of a string for a specific reason (like interacting with a legacy system), you can use mb_strlen($text, '8bit'). This provides the byte count interpretation of strlen.

In summary ๐Ÿ”—

For most modern PHP development, mb_strlen($text, 'utf-8') is the recommended choice for accurate character counting, especially when working with UTF-8 encoded data. It ensures consistency and avoids issues with multibyte characters.

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