<?php $answers = [ [ 'questionid' => '28f68dc4-acc6-4ab7-956d-ca41abf3a4c2', 'answer' => 'Antwoord 89', 'extra' => '', ], [ 'questionid' => '28f-28f68dc4-acc6-4ab7-956d-ca41abf3a4c20', 'answer' => 'Antwoord 20', 'extra' => 'Extra informatie 20', ], [ 'questionid' => 'd8f-28f68dc4-acc6-4ab7-956d-ca41abf3a4c20', 'answer' => 'Antwoord 3', 'extra' => '', ], ]; $questions = [ [ 'questionId' => '28f-28f68dc4-acc6-4ab7-956d-ca41abf3a4c20', 'question' => '1. Question 1', 'type' => 'typequestion/question-text-input', ], ]; $indexedQuestions = []; foreach ($questions as $question) { $id = $question['questionId']; $indexedQuestions[$id] = $question; } foreach ($answers as &$answer) { $id = $answer['questionid']; if (isset($indexedQuestions[$id])) { $answer += $indexedQuestions[$id]; unset($answer['questionId']); } } print_r($answers);