How Can I Filter a PHP Array to Keep Only Elements with a Specific Value, Preserving Original Keys?

Filtering an Array Based on a Value Condition with PHP

An array can be filtered according to a specified condition using built-in PHP functions. Consider the following scenario:

Objective:

Filter an array to retain elements where the value equals 2 and remove all others, preserving the original keys.

Original Array:

$fullArray = array('a' => 2, 'b' => 4, 'c' => 2, 'd' => 5, 'e' => 6, 'f' => 2);

Expected Result:

array('a' => 2, 'c' => 2, 'f' => 2);

Solution:

To achieve this, we can utilize the array_filter() function with a custom callback function that evaluates the value condition. Here's an example:

function filterArray($value){
    return ($value == 2);
}

$filteredArray = array_filter($fullArray, 'filterArray');

foreach($filteredArray as $k => $v){
    echo "$k = $v";
}

In this solution:

• The filterArray() function serves as a callback function for array_filter(), testing each element's value against the condition (returns true for equality to 2).
• The array_filter() function applies the callback to each element and returns a new array containing only the elements that pass the condition.
• The resulting $filteredArray contains the desired elements with the original keys preserved.
• Finally, a loop iterates over the filtered array to display the filtered elements.

This solution provides a straightforward and efficient way to filter an array based on a specific value condition, retaining the original keys, thus meeting the desired outcome.

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