PHP IntlDateFormatter::setPattern() Method: Usage and Examples

When you need to set a custom ICU formatting pattern, it helps to understand both the normal result and what changes with different inputs. This guide focuses on practical examples rather than repeating PHP background material.

IntlDateFormatter::setPattern provides the behavior described below. IntlDateFormatter formats and parses dates using ICU locale conventions and patterns. Its methods may return false on failure.

What Is IntlDateFormatter::setPattern in PHP?

Set a custom icu formatting pattern. IntlDateFormatter formats and parses dates using ICU locale conventions and patterns. Its methods may return false on failure.

Its syntax is:

$formatter->setPattern(...)

Parameters and return value: Read the argument names and optional values in the signature above. Methods use an existing object, while stand-alone functions take direct arguments. The examples demonstrate the relevant arguments and the value returned or the object modified.

Important: ICU pattern letters are not interchangeable with PHP date() specifiers.

Example 1: Basic Usage

This first example demonstrates how to set a custom ICU formatting pattern with a small input.

<?php

$formatter = new IntlDateFormatter("en_US", IntlDateFormatter::NONE, IntlDateFormatter::NONE, "UTC", IntlDateFormatter::GREGORIAN, "yyyy-MM-dd");
$formatter->setPattern("yyyy-MM-dd");
echo $formatter->format(1700000000);

The example uses the simplest useful form. IntlDateFormatter formats and parses dates using ICU locale conventions and patterns. Its methods may return false on failure. The output may depend on the active ICU locale, PHP configuration, or input supplied to the function.

Example 2: Another Case

Here the input or option changes, making it easier to see where the behavior differs. ICU pattern letters are not interchangeable with PHP date() specifiers.

<?php

$formatter = new IntlDateFormatter("en_US", IntlDateFormatter::NONE, IntlDateFormatter::NONE, "UTC", IntlDateFormatter::GREGORIAN, "yyyy-MM-dd");
$formatter->setPattern("EEEE, d MMMM yyyy");
echo $formatter->format(1700000000);

Compare the result to the first example. PHP date() is not locale-aware; IntlDateFormatter uses ICU format tokens.

Practical Example: Applying the Function

This standalone example shows how the same operation fits into a small application task. The intl extension is required for this example.

<?php

$formatter = new IntlDateFormatter("en_US", IntlDateFormatter::NONE, IntlDateFormatter::NONE, "UTC", IntlDateFormatter::GREGORIAN, "yyyy-MM-dd");
$formatter->setPattern("yyyy-MM-dd HH:mm");
echo $formatter->format(1700000000);

The example keeps the operation visible and gives you a starting point for using it in an application. ICU pattern letters are not interchangeable with PHP date() specifiers.

Important Behavior and Edge Cases

• Core behavior: IntlDateFormatter formats and parses dates using ICU locale conventions and patterns. Its methods may return false on failure.
• Return value: Check the result separately from changes to passed-in arrays, iterators, or object state.
• Data constraints: ICU pattern letters are not interchangeable with PHP date() specifiers.
• Environment: The intl extension is required for this example.

Comparison With Related Functions

Common Beginner Mistakes

Key Takeaways

• IntlDateFormatter::setPattern helps you set a custom ICU formatting pattern.
• IntlDateFormatter formats and parses dates using ICU locale conventions and patterns. Its methods may return false on failure.
• ICU pattern letters are not interchangeable with PHP date() specifiers.
• PHP date() is not locale-aware; IntlDateFormatter uses ICU format tokens.

IntlDateFormatter::setPattern is useful when you need to set a custom ICU formatting pattern. Start with the small examples, then adapt the practical example while respecting its input and environment requirements.