


Which PHP Array Function is Right for You: array_map, array_walk, or array_filter?
Oct 29, 2024 am 07:09 AMUnderstanding the Difference between array_map, array_walk, and array_filter
In PHP, these three functions are commonly used for array manipulation. While they share similarities in utilizing callback functions, they differ in their specific behaviors.
array_map:
- Cannot modify the original array.
- Iterates over a single array.
- Returns a new array with transformed values.
- Useful for applying a specific operation to each element in an array.
array_walk:
- Can modify the original array.
- Iterates over a single array.
- Returns true only.
- Useful for performing operations that require access to array keys or altering element values.
array_filter:
- Filters an array based on a predicate function.
- Preserves array keys.
- Returns a new array containing only the elements that satisfy the filter condition.
Key Differences:
To illustrate the differences, let's consider the following example:
<code class="php">$numbers = [2.4, 2.6, 3.5]; $map_result = array_map('floor', $numbers); // Round down each element $walk_result = array_walk($numbers, function (&$v, $k) { $v = floor($v); }); // Round down each element in-place $filter_result = array_filter($numbers, function ($a) { return $a > 2.5; }); // Filter out elements less than 2.5</code>
Output:
- map_result: [2, 2, 3]
- walk_result: true (no return value)
- filter_result: [2.6, 3.5]
As you can see, array_map creates a new transformed array, while array_walk modifies the original array directly. array_filter returns a subset of the original array based on the provided condition.
In conclusion, while array_map, array_walk, and array_filter share similarities, they differ in their capabilities and are best suited for different use cases. Choosing the appropriate function depends on the specific requirements of the task at hand.
The above is the detailed content of Which PHP Array Function is Right for You: array_map, array_walk, or array_filter?. For more information, please follow other related articles on the PHP Chinese website!

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