Assigning null to array element is still considered a valid array element

Question

Why is this still returning a count of 3 ?

$arr =
[
    [
        'slug' => 'products-services-pricing',
        'text' => 'Products/Services and Pricing',
    ],
    [
        'slug' => 'promotions-plan',
        'text' => 'Promotions Plan',
    ],
    (1 == 2) ?
    [
        'slug' => 'distribution-plan',
        'text' => 'Distribution Plan',
    ] : null,
];

echo "Count = ".count($arr)."\n";
print_r($arr);

My foreach is getting messed up. PHP 8.0
I cannot do condition check in foreach because I am using count.

The value of the third element is null, there is no problem with that, no mistery. You are not removing the element, but assigning it a value: null. Here you got an idea: iterate over the array and remove elements valued null. Or simply iterate to count not null elements. — José Carlos PHP
– José Carlos PHP, Commented Nov 17, 2022 at 4:39
@shingo - 74440186/condition-in-array - This question was removed from Stack Overflow for reasons of moderation — anjanesh
– anjanesh, Commented Nov 17, 2022 at 18:08

José Carlos PHP · Accepted Answer · 2022-11-17 10:03:49Z

1

Sure, a null valued element is still considered a valid array element!

For example:

<?php
$arr = [null, null, null];

echo 'Count: ' . count($arr); //Will print 3

In your code, the value of the third element is null, there is no problem with that, no mistery. You are not removing the element, but assigning it a value: null.

Here you got an idea: iterate over the array and remove elements valued null:

$aux = [];
foreach ($arr as $item) {
    if (!is_null($item)) {
        $aux[] = $item;
    }
}
$arr = $aux; //Now $arr has no null elements

Or simply iterate to count not null elements.

$c = 0;
foreach ($arr as $item) {
    if (!is_null($item)) {
        $c++;
    }
}
echo 'Count: ' . $c; //Count without null elements

Or you can build your array adding or not the conditional element. This can be the better solution:

$arr =
[
    [
        'slug' => 'products-services-pricing',
        'text' => 'Products/Services and Pricing',
    ],
    [
        'slug' => 'promotions-plan',
        'text' => 'Promotions Plan',
    ],
];

if (1 == 2) {
    $arr[] = [
        'slug' => 'distribution-plan',
        'text' => 'Distribution Plan',
    ];
}

echo 'Count: ' . count($arr); //Will print 2

edited Nov 17, 2022 at 10:03

answered Nov 17, 2022 at 4:48

José Carlos PHP

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2 Comments

anjanesh Over a year ago

This is a more work since the actual array is a multi-dimensional one - is there a way to do if condition in the array assignment as opposed to using ternary operator ?

José Carlos PHP Over a year ago

Sure, you can build your array adding or not the conditional element. I edited my answer, look last code sample. Maybe is the better and more efficient way to goal what you want.

mickmackusa · Accepted Answer · 2022-11-17 05:35:02Z

0

If you change the values returned by your ternary and use the spread operator, you'll be able to achieve what you want without any subsequent filtering or fooling around.

Code: (Demo)

...(1 == 2)
    ? [['slug' => 'distribution-plan', 'text' => 'Distribution Plan']]
    : [],

By adding a level of depth to the true branch value, the spread operator will push the single row into the array.

By changing null to an empty array, the spread operator will push nothing into the array.

Kind of, sort of, related:

PHP is there a way to add elements calling a function from inside of array

answered Nov 17, 2022 at 5:35

mickmackusa♦

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Comments

Serious Angel · Accepted Answer · 2024-09-25 18:22:47Z

It should be possible to spread a cast value relatively similarly to JavaScript.

JavaScript

console.log([1, 2, ...([].concat(null ?? []))]);
console.log([1, 2, ...([].concat(3 ?? []))]);

[ 1, 2 ]
[ 1, 2, 3 ]

PHP

$a = null;
$b = '123';
$c = 456;
$d = [789];

$r = [
    // Spread empty array won't result in any value.

    ...[],
    ...(null ?? []),
    ...((array) null ?? []),
    ...($a ?? []),
    ...((array) $a ?? []),

    // Cast is required to wrap into arrays to spread.
    // ...($b ?? []), // Fatal error: Uncaught Error: Only arrays and Traversables can be unpacked...

    ...((array) $b ?? []),
    ...((array) $c ?? []),
    ...((array) $d ?? [])
];

var_dump(null, (array) null, $r);

NULL
array(0) {}
array(3) {
  [0]=> string(3) "123"
  [1]=> int(456)
  [2]=> int(789)
}

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