PHP sort array by two field values [duplicate]

I've an array like this

Array (
 [0] => Array( "destination" => "Sydney",
               "airlines" => "airline_1",
               "one_way_fare" => 100,
               "return_fare => 300
       ),
 [2] => Array( "destination" => "Sydney",
               "airlines" => "airline_2",
               "one_way_fare" => 150,
               "return_fare => 350
       ),
 [3] => Array( "destination" => "Sydney",
               "airlines" => "airline_3",
               "one_way_fare" => 180,
               "return_fare => 380
       )
)

How can i sort the value by return_fare asc , one_way_fare asc ?

I tried array_multisort() but i ended up getting mixed up data..

asort only works for one dimensional array, i need to sort by two values or more, how can i achieve this like in SQL, order by field1 asc,field2 asc ?

Solution 1:

array_multisort() is the correct function, you must have messed up somehow:

// Obtain a list of columns
foreach ($data as $key => $row) {
    $return_fare[$key]  = $row['return_fare'];
    $one_way_fare[$key] = $row['one_way_fare'];
}

// Sort the data with volume descending, edition ascending
array_multisort($return_fare, SORT_ASC, $one_way_fare, SORT_ASC, $data);

If you take a look at the comments at PHP's manual page for array_multisort(), you can find a very helpful array_orderby() function which allows you to shorten the above to just this:

$sorted = array_orderby($data, 'return_fare', SORT_ASC, 'one_way_fare', SORT_ASC);

To avoid the looping use array_column() (as of PHP 5.5.0):

array_multisort(array_column($data, 'return_fare'),  SORT_ASC,
                array_column($data, 'one_way_fare'), SORT_ASC,
                $data);

Solution 2:

In addition to array_multisort(), which requires you to build column-arrays first, there is also usort() which doesn't require such a thing.

usort($data, function($a, $b) { 
    $rdiff = $a['return_fare'] - $b['return_fare'];
    if ($rdiff) return $rdiff; 
    return $a['one_way_fare'] - $b['one_way_fare']; 
}); // anonymous function requires PHP 5.3 - use "normal" function earlier

Solution 3:

Another example using the spaceship operator.

usort($data, function($a, $b) { 
    return $a['return_fare'] <=> $b['return_fare'] ?: $a['one_way_fare'] <=> $b['one_way_fare'];
});