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

Changing PHP Array Values in a Foreach Loop (Duplicate Fix)

In multidimensional arrays, traversing through each element using a foreach loop can present complexities when attempting to modify the original array.

Consider the following example:

$fields = [
    "names" => [
        "type" => "text",
        "class" => "name",
        "name" => "name",
        "text_before" => "name",
        "value" => "",
        "required" => true,
    ]
];

Now, suppose you have a function that checks if required inputs are filled in:

function checkForm($fields) {
    foreach ($fields as $field) {
        if ($field['required'] && strlen($_POST[$field['name']]) <= 0) {
            $fields[$field]['value'] = "Some error"; // Here's the issue
        }
    }
    return $fields;
}

The problematic line is $fields[$field]['value'] = "Some error";. To modify the original array, you need to access the key of the current element instead of the value, as shown below:

foreach ($fields as $key => $field) {
    if ($field['required'] && strlen($_POST[$field['name']]) <= 0) {
        $fields[$key]['value'] = "Some error";
    }
}

Note the use of $key within $fields[$key]['value'] to reference the key of the current element in the outer loop. This ensures that the original array is modified as intended.

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