How Can I Sort a Multidimensional Array in PHP Based on a Unix Timestamp?

Sorting a Multidimensional Array in PHP

Objective

To sort a multidimensional array based on the unix timestamp stored in the sub-array "x".

Solution

To achieve this, you can utilize a custom comparison function in conjunction with the usort function.

Custom Comparison Function

<code class="php">function compare($x, $y) {
    if ($x[4] == $y[4])
        return 0;
    else if ($x[4] < $y[4])
        return -1;
    else
        return 1;
}</code>

Applying the Function with usort

<code class="php">usort($arrayOfArrays, 'compare');</code>

Further Clarification

The usort function expects a comparison function as its second argument, which takes two elements from the array and returns a negative value if the first element should be placed before the second element, a zero value if they should appear in the same order, and a positive value if the first element should be placed after the second element.

This custom function compares the unix timestamp values in the fourth position of each sub-array. If the timestamps are equal, it returns 0. If the first timestamp is earlier than the second, it returns -1. Otherwise, it returns 1, indicating that the second sub-array should appear after the first.

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