PHP - 使用array_unique（）从数组中删除重复项

There's been discussions about this topic before, but I haven't been able to get any of the examples from them to work in my case. Hoping this is an easy fix that may help others having similar problems.

I have an html form that takes a series of 5 numbers as an array. I simply want to print the numbers without any duplicates. I'm trying to accomplish this using array_unique().

The Form:

<p>Enter a series of numbers.  Any duplicates will be removed, then 
displayed on the screen.</p>
<form action="rDuplicate.php" method="post">
Number 1: <input type="number" name="number[]"><br>
Number 2: <input type="number" name="number[]"><br>
Number 3: <input type="number" name="number[]"><br>
Number 4: <input type="number" name="number[]"><br>
Number 5: <input type="number" name="number[]"><br>
<input type="submit">
</form>

The PHP:

<?php 
    $values = array($_POST);
    $result = array_unique($values);
    print_r($result);
?>

Current Sample Output:

Array ( [number] => Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 2 [4] => 1 ) )

<?php
$numbers = $_POST['number']  ?? [];
$numbers = is_array($numbers)
                ? array_filter($numbers, 'ctype_digit')
                : [];
$numbers = array_unique($numbers);

var_dump($numbers);

Long form:

if(isset($_POST['number']))
{
    $numbers = $_POST['number'];
} else {
    $numbers = [];
}
if(is_array($numbers)) {
    $numbers = array_filter($numbers, 'ctype_digit');
} else {
    $numbers = [];
}
$numbers = array_unique($numbers);   

In the long hand version, we can use the ternary operator to contract the if else:

$numbers = isset($_POST['number']) ? $_POST['number'] : [];

We can contract that further with the null coalescing operator:

$numbers = $_POST['number'] ?? [];

If you want to ensure you only have an array of integers (or more precisely integers in strings) passed from your form, you can filter your array.

$numbers = array_filter($numbers, 'ctype_digit');

Note: You cannot trust user input.