When working with PHP, you may need to assemble locale components into a locale identifier. This guide explains the operation, shows what its arguments mean, and uses three separate examples to make the result easier to understand.
Locale::composeLocale: A locale is made of language, optional region and optional script subtags.
What Is Locale::composeLocale in PHP?
Assemble locale components into a locale identifier. A locale is made of language, optional region and optional script subtags.
Syntax:
Locale::composeLocale(array $subtags): ?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: Only supported component keys should be supplied; validate language codes taken from user input.
Example 1: Basic Usage
This example introduces the operation with a short and predictable input.
<?php
echo Locale::composeLocale(["language" => "en", "region" => "US"]);
The code focuses on the main operation. A locale is made of language, optional region and optional script subtags.
Example 2: Another Case
Now compare a different input, locale, date, or option to see another part of the behavior.
<?php
echo Locale::composeLocale(["language" => "zh", "script" => "Hant", "region" => "TW"]);
What changes? Only supported component keys should be supplied; validate language codes taken from user input.
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
$region = "CA";
$language = "fr";
$localeId = Locale::composeLocale(["language" => $language, "region" => $region]);
echo $localeId;
The practical example demonstrates how to apply this operation to multiple values, a reusable task, or a validated input. A locale is made of language, optional region and optional script subtags.
Important Behavior and Edge Cases
- Core behavior: A locale is made of language, optional region and optional script subtags.
- Inputs and results: Only supported component keys should be supplied; validate language codes taken from user input.
- Alternatives: Locale::parseLocale() decomposes a locale identifier into its parts.
- Compatibility: The intl extension is required.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
Locale::composeLocale | Assemble locale components into a locale identifier. |
| Related PHP approach | Locale::parseLocale() decomposes a locale identifier into its parts. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Using an incorrect input or option | Only supported component keys should be supplied; validate language codes taken from user input. |
| Confusing this API with a related operation | Locale::parseLocale() decomposes a locale identifier into its parts. |
| Assuming output is identical across environments | Check return values and required extensions or versions. The intl extension is required. |
Key Takeaways
- Locale::composeLocale helps you assemble locale components into a locale identifier.
- A locale is made of language, optional region and optional script subtags.
- Only supported component keys should be supplied; validate language codes taken from user input.
Use Locale::composeLocale when you need to assemble locale components into a locale identifier. 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.