When working with PHP, you may need to replace the number formatter ICU pattern. This guide explains the operation, shows what its arguments mean, and uses three separate examples to make the result easier to understand.
NumberFormatter::setPattern: ICU patterns can specify grouping and decimal digits.
What Is NumberFormatter::setPattern in PHP?
Replace the number formatter ICU pattern. ICU patterns can specify grouping and decimal digits.
Syntax:
$formatter->setPattern(string $pattern): bool
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: Invalid ICU patterns may fail. A pattern does not change the underlying numeric value.
Example 1: Basic Usage
This example introduces the operation with a short and predictable input.
<?php
$formatter = new NumberFormatter("en_US", NumberFormatter::PATTERN_DECIMAL, "#,##0.0");
$formatter->setPattern("#,##0.00");
echo $formatter->format(12.5);
The code focuses on the main operation. ICU patterns can specify grouping and decimal digits.
Example 2: Another Case
Now compare a different input, locale, date, or option to see another part of the behavior.
<?php
$formatter = new NumberFormatter("en_US", NumberFormatter::PATTERN_DECIMAL, "#,##0");
$formatter->setPattern("00000");
echo $formatter->format(42);
What changes? Invalid ICU patterns may fail. A pattern does not change the underlying numeric value.
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
$formatter = new NumberFormatter("en_US", NumberFormatter::PATTERN_DECIMAL, "#,##0");
foreach (["0000", "#,##0.00"] as $pattern) {
if ($formatter->setPattern($pattern)) {
echo $formatter->format(27.5) . PHP_EOL;
}
}
The practical example demonstrates how to apply this operation to multiple values, a reusable task, or a validated input. ICU patterns can specify grouping and decimal digits.
Important Behavior and Edge Cases
- Core behavior: ICU patterns can specify grouping and decimal digits.
- Inputs and results: Invalid ICU patterns may fail. A pattern does not change the underlying numeric value.
- Alternatives: NumberFormatter::getPattern() returns the active pattern.
- Compatibility: The intl extension is required.
Comparison With Related Functions
| Function or Approach | When to Use It |
|---|---|
NumberFormatter::setPattern | Replace the number formatter icu pattern. |
| Related PHP approach | NumberFormatter::getPattern() returns the active pattern. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Using an incorrect input or option | Invalid ICU patterns may fail. A pattern does not change the underlying numeric value. |
| Confusing this API with a related operation | NumberFormatter::getPattern() returns the active pattern. |
| Assuming output is identical across environments | Check return values and required extensions or versions. The intl extension is required. |
Key Takeaways
- NumberFormatter::setPattern helps you replace the number formatter ICU pattern.
- ICU patterns can specify grouping and decimal digits.
- Invalid ICU patterns may fail. A pattern does not change the underlying numeric value.
Use NumberFormatter::setPattern when you need to replace the number formatter ICU pattern. 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.