How Can I Modify Array Values Directly Within a PHP Foreach Loop?

Editing Array Values within a Foreach Loop

In PHP, when iterating over an array using a foreach loop, it's possible to modify the current element being processed. This allows us to manipulate the array values during the iteration itself.

To edit the current object within a foreach loop, there are two common approaches:

1. Using Preserving Key

foreach ($questions as $key => $question) {
    $questions[$key]['answers'] = $answers_model->get_answers_by_question_id($question['question_id']);
}

In this approach, we preserve the array keys by utilizing $key => $question. This allows us to update the associated element in the main $questions variable.

2. Using Reference Assignment

foreach ($questions as &$question) {
    $question['answers'] = $answers_model->get_answers_by_question_id($question['question_id']);
}

Here, the & preceding $question indicates reference assignment. This means that the $question variable inside the loop directly modifies the array element.

According to PHP documentation, "In order to be able to directly modify array elements within the loop, precede $value with &. In that case, the value will be assigned by reference."

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