When working with PHP, you may need to convert Unicode text using a selected case-conversion mode. This guide explains the operation, shows what its arguments mean, and uses three separate examples to make the result easier to understand.
mb_convert_case: Unlike byte-oriented case functions, this operation applies Unicode case mappings.
What Is mb_convert_case in PHP?
Convert Unicode text using a selected case-conversion mode. Unlike byte-oriented case functions, this operation applies Unicode case mappings.
Syntax:
mb_convert_case(string $string, int $mode, ?string $encoding = null): string
Parameters and return value: The signature above identifies the arguments and return type where the API has a single call. For topic guides, follow the sequence of calls in the examples. Always distinguish a returned value from an object or variable modified by reference.
Important: Case conversion is not equivalent to locale-sensitive collation and can change text length.
Example 1: Basic Usage
This example introduces the operation with a short and predictable input.
<?php
echo mb_convert_case("HELLO WORLD", MB_CASE_TITLE, "UTF-8");
The code focuses on the main operation. Unlike byte-oriented case functions, this operation applies Unicode case mappings.
Example 2: Another Case
Now compare a different input, locale, date, or option to see another part of the behavior.
<?php
echo mb_convert_case("ÉCOLE", MB_CASE_LOWER, "UTF-8");
What changes? Case conversion is not equivalent to locale-sensitive collation and can change text length.
Practical Example: Applying It in an Application
Use the following separate example as a starting point for a small application task. Check any extension or environment requirements below before running it.
<?php
$headings = ["PROJECT STATUS", "WEEKLY REPORT"];
foreach ($headings as $heading) {
echo mb_convert_case($heading, MB_CASE_TITLE, "UTF-8") . PHP_EOL;
}
The practical example demonstrates how to apply this operation to multiple values, a reusable task, or a validated input. Unlike byte-oriented case functions, this operation applies Unicode case mappings.
Important Behavior and Edge Cases
- Core behavior: Unlike byte-oriented case functions, this operation applies Unicode case mappings.
- Inputs and results: Case conversion is not equivalent to locale-sensitive collation and can change text length.
- Alternatives: mb_strtolower() and mb_strtoupper() provide simpler fixed conversions.
- Compatibility: mbstring is required for mb_* functions.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
mb_convert_case | Convert unicode text using a selected case-conversion mode. |
| Related PHP approach | mb_strtolower() and mb_strtoupper() provide simpler fixed conversions. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Using an incorrect input or option | Case conversion is not equivalent to locale-sensitive collation and can change text length. |
| Confusing this API with a related operation | mb_strtolower() and mb_strtoupper() provide simpler fixed conversions. |
| Assuming output is identical across environments | Check return values and required extensions or versions. mbstring is required for mb_* functions. |
Key Takeaways
- mb_convert_case helps you convert Unicode text using a selected case-conversion mode.
- Unlike byte-oriented case functions, this operation applies Unicode case mappings.
- Case conversion is not equivalent to locale-sensitive collation and can change text length.
Use mb_convert_case when you need to convert Unicode text using a selected case-conversion mode. Start with the first example, compare the second, and adapt the practical example to your inputs. Confirm the return value and environment requirements before adding it to production code.