How to Efficiently Find Minimum and Maximum Values in a Nested PHP Array?

Retrieve Minimum and Maximum Values from PHP Array

Problem:

Given a nested PHP array, determine how to efficiently extract the minimum and maximum values for a specific key.

Example:

<code class="php">$array = [
    [
        'id' => '20110209172713',
        'Date' => '2011-02-09',
        'Weight' => '200',
    ],
    [
        'id' => '20110209172747',
        'Date' => '2011-02-09',
        'Weight' => '180',
    ],
    [
        'id' => '20110209172827',
        'Date' => '2011-02-09',
        'Weight' => '175',
    ],
    [
        'id' => '20110211204433',
        'Date' => '2011-02-11',
        'Weight' => '195',
    ],
];</code>

Solution:

Option 1: Using array_column() and min()/max()

This method leverages the array_column() function to extract the 'Weight' values into a numerical array. The min() and max() functions are then used to determine the minimum and maximum values, respectively.

<code class="php">$weights = array_column($array, 'Weight');
$minValue = min($weights);
$maxValue = max($weights);</code>

Option 2: Using array_map()

Similar to Option 1, this method utilizes array_map() to extract the 'Weight' values. However, it requires a custom function to perform the mapping.

<code class="php">$weights = array_map(function($item) {
    return $item['Weight'];
}, $array);

$minValue = min($weights);
$maxValue = max($weights);</code>

Option 3 (deprecated): Using nested loops

This method is not recommended as it is relatively inefficient, especially for large arrays.

<code class="php">$minValue = INF;
$maxValue = -INF;

foreach ($array as $item) {
    if ($item['Weight'] < $minValue) {
        $minValue = $item['Weight'];
    }

    if ($item['Weight'] > $maxValue) {
        $maxValue = $item['Weight'];
    }
}</code>

Option 4: Using array_reduce()

This method is useful for specific scenarios where you need to perform additional calculations or processing while determining the minimum or maximum value.

<code class="php">$minValue = array_reduce($array, function($min, $item) {
    return min($min, $item['Weight']);
}, PHP_INT_MAX);

$maxValue = array_reduce($array, function($max, $item) {
    return max($max, $item['Weight']);
}, -PHP_INT_MAX);</code>

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