Sorting a multidimensional array by element containing date. Use the usort() function to sort the array. The usort() function is PHP builtin function that sorts a given array using user-defined comparison function. This function assigns new integral keys starting from zero to array elements.
Syntax:
boolean usort( $array, "function_name")
Parameters: This function accepts two parameters as shown in the above syntax and are described below:
- $array: This parameter specifies the array which u want to sort.
- function_name: This parameter specifies the name of a user-defined function which compares the values and sort the array specified by the parameter $array. This function returns an integer value based on the following conditions. If two argument are equal then it returns 0, If first argument is greater than second, it returns 1 and if first argument is smaller than second, it returns -1.
Return Value: This function returns Boolean type value. It returns TRUE in case of success and FALSE in case of failure.
We use strtotime to convert given time string to a timestamp object. Once we have timestamps, we subtract them to decide greater.
Program:
<?php   // Declare a multidimensional array // and initialize it $array = Array (     Array (         "gfg" => "GFG_1",         "datetime" => "2019-02-22 11:29:45",         ),     Array (         "gfg" => "GFG_2",         "datetime" => "2019-02-13 11:29:45",     ),     Array (         "gfg" => "GFG_3",         "datetime" => "2019-02-15 11:29:45",     ) );   // Comparison function function date_compare($element1, $element2) {     $datetime1 = strtotime($element1['datetime']);     $datetime2 = strtotime($element2['datetime']);     return $datetime1 - $datetime2; }   // Sort the array usort($array, 'date_compare');   // Print the array print_r($array)   ?> |
Output:
Array
(
[0] => Array
(
[gfg] => GFG_2
[datetime] => 2019-02-13 11:29:45
)
[1] => Array
(
[gfg] => GFG_3
[datetime] => 2019-02-15 11:29:45
)
[2] => Array
(
[gfg] => GFG_1
[datetime] => 2019-02-22 11:29:45
)
)
