Which PHP Array Function is Right for You: array_map, array_walk, or array_filter?

Understanding 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.

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