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<?php $arr = array ( Array ( "contact_id" => 5000, 'invoice' => 476 ), Array ( 'contact_id' => 5000, 'invoice' => 396 ), Array ( 'contact_id' => 1490, 'invoice' => 1083 ), Array ( 'contact_id' => 1490, 'invoice' => 498 )); $res =array(); Foreach($arr as $subarr){ Foreach($subarr as $key => $val){ If($key == "contact_id") { If(!isset($res[$val])) $res[$val] = array(); $cid = $val; }Else{ $res[$cid][]= $val; } } } Var_dump($res);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.34, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
array(2) { [5000]=> array(2) { [0]=> int(476) [1]=> int(396) } [1490]=> array(2) { [0]=> int(1083) [1]=> int(498) } }

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