php - Find repeating values in multidimensional array -

i'm trying find when array has 2nd dimension values same can deal them.

i've looked @ array_unique , other people asking similar question, delete values instead of returning them.

say have array this:

array(     [0] => array(         [laps] => 7,         [corrected_time] => 18     ),     [1] => array(         [laps] => 6,         [corrected_time] => 18     ),     [2] => array(         [laps] => 7,         [corrected_time] => 18.5     ) ) 

i'd have return: array(0,1) because both have same value corrected time

here 1 approach. first values corrected_time , convert them strings (because we'll use them in array_count_values, works on ints , strings).

$times = array_map('strval', array_column($your_array, 'corrected_time')); 

then find values occur more once using array_count_values , array_filter.

$repeats = array_filter(array_count_values($times), function($time) {     return $time > 1; }); 

after have list of repeated times, can use filter original array include items repeated times.

$multiples = array_filter($your_array, function($item) use ($repeats){     return isset($repeats[(string) $item['corrected_time']]); }); 

you can iterate on this, or if want keys, can them with

$keys = array_keys($multiples);