When working with PHP, you may need to convert one or more variables by reference. This guide explains the operation, shows what its arguments mean, and uses three separate examples to make the result easier to understand.
mb_convert_variables: The conversion is applied directly to referenced variables, including string values nested inside arrays.
What Is mb_convert_variables in PHP?
Convert one or more variables by reference. The conversion is applied directly to referenced variables, including string values nested inside arrays.
Syntax:
mb_convert_variables(string $toEncoding, array|string $fromEncoding, mixed &$var, mixed &...$vars): string|false
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: Variables are modified in place. A copy may be required if the original bytes must be preserved.
Example 1: Basic Usage
This example introduces the operation with a short and predictable input.
<?php
$title = "Caf\xE9";
mb_convert_variables("UTF-8", "ISO-8859-1", $title);
echo $title;
The code focuses on the main operation. The conversion is applied directly to referenced variables, including string values nested inside arrays.
Example 2: Another Case
Now compare a different input, locale, date, or option to see another part of the behavior.
<?php
$data = ["city" => "Z\xFCrich"];
mb_convert_variables("UTF-8", "ISO-8859-1", $data);
print_r($data);
What changes? Variables are modified in place. A copy may be required if the original bytes must be preserved.
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
$customer = ["name" => "M\xFCller", "city" => "K\xF6ln"];
$sourceEncoding = mb_convert_variables("UTF-8", "ISO-8859-1", $customer);
echo $sourceEncoding . PHP_EOL;
print_r($customer);
The practical example demonstrates how to apply this operation to multiple values, a reusable task, or a validated input. The conversion is applied directly to referenced variables, including string values nested inside arrays.
Important Behavior and Edge Cases
- Core behavior: The conversion is applied directly to referenced variables, including string values nested inside arrays.
- Inputs and results: Variables are modified in place. A copy may be required if the original bytes must be preserved.
- Alternatives: mb_convert_encoding() returns converted data rather than updating references.
- Compatibility: mbstring is required for mb_* functions.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
mb_convert_variables | Convert one or more variables by reference. |
| Related PHP approach | mb_convert_encoding() returns converted data rather than updating references. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Using an incorrect input or option | Variables are modified in place. A copy may be required if the original bytes must be preserved. |
| Confusing this API with a related operation | mb_convert_encoding() returns converted data rather than updating references. |
| Assuming output is identical across environments | Check return values and required extensions or versions. mbstring is required for mb_* functions. |
Key Takeaways
- mb_convert_variables helps you convert one or more variables by reference.
- The conversion is applied directly to referenced variables, including string values nested inside arrays.
- Variables are modified in place. A copy may be required if the original bytes must be preserved.
Use mb_convert_variables when you need to convert one or more variables by reference. 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.