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<?php $search = 'pink'; $test = array( 'name_01' => array('yellow', 'red', 'blue', 'black', 'white', 'purple'), 'name_02' => array('red', 'blue', 'white', 'green'), 'name_03' => array('blue', 'pink', 'purple', 'blue'), 'name_04' => array('white', 'black', 'red'), 'name_05' => array('yellow', 'white', 'pink', 'black') ); $keys = []; foreach($test as $key=>$arr){ if(in_array($search,$arr)){ $keys[] = $key; } } print_r($keys);

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