PHP - Find whether an array element is odd or even

Question

I'm having an array of items like this:

$data = array(
            'item1' => array( // is even
                'icon' => 'commenting',
                'content' => 'Lorem ipsum dolor sit amet, consectetur adipisicing elit. ',
            ), 
            'item2' => array(// is odd
                'icon' => 'sticky-note',
                'content' => 'Debitis id eligendi assumenda, cumque optio veniam eos perferendis molestias explicabo odit',
            ),
            'item3' => array(// is even
                'icon' => 'users',
                'content' => 'Libero, suscipit, quos. Quae praesentium tempore minima quod tempora odio',
            ),
            'item4' => array(// is odd
                'icon' => 'thumbs-o-up',
                'content' => 'Lorem ipsum dolor sit amet, consectetur adipisicing elit. ',
            ),
            'item5' => array(// is even
                'icon' => 'wrench',
                'content' => 'Debitis id eligendi assumenda, cumque optio veniam eos perferendis molestias explicabo odi',
            ),
        );

What I want to do is, when I loop through the elements of the array in order to output them, to detect whether each element is odd or even, for instance:

foreach ($data as $key => $value) {
    echo '<h1>' . $key . '</h1>';
    echo '<p>' . $value['icon'] . '</p>';
    echo '<p>' . $value['content'] . '</p>';
    echo '<p> (Item is odd or even) </p>'; // * Show wheather is odd or even here
}

Do you mean if the number of they key is even/odd ?! e.g. `itemX` if X is even or not ? — Rizier123, Aug 17 '15 at 12:12
No the key may not contain numbers at all.. the items themselves whether they are odd/even — ltdev, Aug 17 '15 at 12:13
I still don't get it. What do you want to check? Do you want to check if the inner array has an even/odd amount of elements? Or if the key is even/odd, when you would assume a 0-based indexed array? — Rizier123, Aug 17 '15 at 12:15
If this is used for styling, there's a nice CSS selector that styles just even or odd childs ([see this answer](http://stackoverflow.com/a/5080787/1677209)) — T30, Apr 19 '17 at 11:10
[This answer](https://stackoverflow.com/a/24726403/2943403) demonstrates how to maintain the counter and check for oddness. — mickmackusa, May 19 '23 at 22:03

John Bupit · Accepted Answer · 2015-11-26T07:11:14.303

7

Just declare a counter and iterate.

$counter = 1;
foreach ($data as $key => $value) {
    echo '<h1>' . $key . '</h1>';
    echo '<p>' . $value['icon'] . '</p>';
    echo '<p>' . $value['content'] . '</p>';
    echo '<p> ' . (($counter % 2)? 'odd': 'even') . ' </p>'; // * Show whether the position is odd or even here
    $counter++;
}

edited Nov 26 '15 at 07:11

answered Aug 17 '15 at 12:13

John Bupit

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Why the need for a counter if you're using a $key to index? – Jack hardcastle Aug 17 '15 at 12:14
@Jackhardcastle This is an associative array. The `$key`s would be `'item1', 'item2',` and so on. – John Bupit Aug 17 '15 at 12:16
Yep, just noticed. My bad – Jack hardcastle Aug 17 '15 at 12:16
I was wondering whether php had a build in function that could do this, or getting all odd or even elements from the array, but this works too for me.. anyway thanks! – ltdev Aug 17 '15 at 13:30

Script47 · Answer 2 · 2023-05-19T18:57:39.827

3

Using the below code you'd substitute $yourNumber with the variable you want to check. The if statement checks if it is even, and the else will run if it is odd.

<?php
if ($yourNumber % 2 == 0) {
    echo "It is even.";
} else {
    echo "It is odd.";
}
?>

We use the Modulo to check if it's odd/even.

edited May 19 '23 at 18:57

answered Aug 17 '15 at 12:11

Script47

14,230
4
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score 3 · Answer 3 · answered Aug 17 '15 at 12:14

$i = 1;
foreach ($data as $key => $value) {
    echo '<h1>' . $key . '</h1>';
    echo '<p>' . $value['icon'] . '</p>';
    echo '<p>' . $value['content'] . '</p>';
    echo '<p> ' . (($i % 2)? 'odd': 'even') . ' </p>'; // * Show wheather is odd or even here
    $i++;
}

score 1 · Answer 4 · answered Aug 17 '15 at 12:27

You can use a counter, the modulus operator and an array to map strings to the result:

$map=['This item is: Even','Whilst this one is: Odd'];
$i=1;
foreach ($data as $key => $value): $i++;?>
    <h1> <?= $key;?> </h1>
    <p> <?= $value['icon'];?> </p>
    <p> <?= $value['content'];?> </p>
    <p> <?= $map[$i % 2];?> </p>
<?php endforeach;?>

score 0 · Answer 5 · answered Aug 17 '15 at 12:13

Can go for the below code :

$i = 1;
 foreach ((array) $data as $key => $value) {
    if($i % 2 == 0) $item = 'even';
    else $item = 'odd';
    echo '<h1>' . $key . '</h1>';
    echo '<p>' . $value['icon'] . '</p>';
    echo '<p>' . $value['content'] . '</p>';
    echo '<p> (Item is '.$item.') </p>'; // * Show wheather is odd or even here
    ++$i;
}

PHP - Find whether an array element is odd or even

5 Answers5