PHP Getting "undefined offset" when Trying to Access Elements in Multidimensional Arrays

Question

I have the following array:

<?php
$bridal_artists = array(
    array(
        'id' => 1,
        'name' => 'Artist 01',
        'section' => array( 'engagement', 'wedding' ),
        'featured_img' => array( 'engagement' => 0, 'wedding' => 2 ),
        'images' => array(
            array( 'artist01-01.jpg', 'Classic Anne Engagement Ring' ),
            array( 'artist01-02.jpg', 'Wonky Diamond Band, 0.09ctw diamonds' ),
            array( 'artist01-03.jpg', 'Two Row Pavé Band, 0.24ctw diamonds' ),
            array( 'artist01-04.jpg', 'Narrow Pavé Diamond Band, 0.36ctw diamonds' ),
            array( 'artist01-05.jpg', 'Leslie Engagement Ring' ),
            array( 'artist01-06.jpg', 'Four Claw Pavé Diamond Engagement Ring' ),
            array( 'artist01-07.jpg', 'Louisa Engagement Ring' ),
            array( 'artist01-08.jpg', 'Original Halo Engagement Ring' ),
            array( 'artist01-09.jpg', 'Bark Textured Solitaire Engagement Ring' ),
            array( 'artist01-10.jpg', 'Alexa Engagement Ring' ),
            array( 'artist01-11.jpg', 'Dancing Diamond Engagement Ring' ),
            array( 'artist01-12.jpg', 'Trinity Engagement Ring' ),
            array( 'artist01-13.jpg', 'Scalloped Engagement Ring' ),
            array( 'artist01-14.jpg', 'Cushion Double Halo Engagement Ring' ),
            array( 'artist01-15.jpg', 'Triple Illusion Cushion Engagement Ring' ),
            array( 'artist01-16.jpg', 'Marion Engagement Ring' ),
        ),
    ),
    array(
        'id' => 2,
        'name' => 'Artist 2',
        'section' => array( 'engagement', 'wedding' ),
        'featured_img' => array( 'engagement' => 0, 'wedding' => 2 ),
        'images' => array(
            array( 'artist02-01.jpg', 'Bamboo Damascus Steel Band' ),
            array( 'artist02-02.jpg', 'Infinity Damascus Steel Band yellow gold liner and rails' ),
            array( 'artist02-03.jpg', 'Vortex Damascus Steel Band white gold liner and rails' ),
            array( 'artist02-04.jpg', 'Wood Grain Damascus Steel Band' ),
            array( 'artist02-05.jpg', 'Hailey Engagement Ring  damascus steel and gold with 0.25ct diamond' ),
            array( 'artist02-06.jpg', 'Beech Mokume-gane Band 18k yellow gold, palladium, sterling silver' ),
            array( 'artist02-07.jpg', 'Arcturus Meteorite Band, white gold, meteorite' ),
            array( 'artist02-08.jpg', 'Arcturus Meteorite Band, yellow gold, meteorite' ),
            array( 'artist02-09.jpg', 'Sirius Meteorite Band, meteorite, white gold liner and rails' ),
            array( 'artist02-10.jpg', 'Sirius Meteorite Band, meteorite, yellow gold liner and rails' ),
        ),
    ),
    array(
        'id' => 3,
        'name' => 'Artist 3',
        'section' => array( 'wedding' ),
        'featured_img' => array( 'wedding' => 1 ),
        'images' => array(
            array( 'artist03-01.jpg', 'ACE000 Mokume-gane band, 18k yellow gold, 14k white and rose gold, sterling silver, etched finish' ),
            array( 'artist03-02.jpg', 'ACE000 Mokume-gane band, 18k yellow gold, 14k white and rose gold, sterling silver, smooth finish' ),
            array( 'artist03-03.jpg', 'ZCE000 Mokume-gane band, sterling silver, palladium, tight wood-grain etched finish' ),
            array( 'artist03-04.jpg', 'ACN000 Mokume-gane band, 18k yellow gold, 14k white and rose gold, sterling silver, smooth finish' ),
            array( 'artist03-05.jpg', 'HCN000 Mokume-gane band, 14k white and rose gold, sterling silver, smooth finish' ),
            array( 'artist03-06.jpg', 'CCE000 Mokume-gane band, 14k white gold, palladium, sterling silver, etched finish' ),
        ),
    ),
    array(
        'id' => 4,
        'name' => 'Artist 4',
        'section' => array( 'engagement', 'wedding' ),
        'featured_img' => array( 'engagement' => 4, 'wedding' => 1 ),
        'images' => array(
            array( 'artist04-01.jpg', 'Cava Engagement Ring' ),
            array( 'artist04-02.jpg', 'Cava Ch Rd Band, 0.14ctw diamonds' ),
            array( 'artist04-03.jpg', 'Iris Pavé Engagement Ring, 0.19ctw diamond sides' ),
            array( 'artist04-04.jpg', 'Perth Pavé Engagement Ring and Band, 0.24ctw diamond sides' ),
            array( 'artist04-05.jpg', 'Poppy Engagement Ring, 0.22ctw diamond sides' ),
            array( 'artist04-06.jpg', 'Poppy Pavé Band, 0.17ctw sides' ),
            array( 'artist04-07.jpg', 'Sanday Engagement Ring' ),
            array( 'artist04-08.jpg', 'Scotasay Engagement Ring, 0.55ctw diamond sides' ),
        ),
    ),
);
?>

The array holds the relevant data per each artist. Multidimensional, as seen above. I used a foreach loop to iterate through all of them then a second one to loop through the main keys. However, when I try to use a key name, I get "undefined offset." I tried the numeric offset and that gives me "illegal string offset" instead.

        <?php foreach ($bridal_artists as $artist): ?>
            <?php foreach ($artist as $key => $value): ?>
                <?php if($key[2][0] == $cat || $value[2][1] == $cat): ?>
                   rest of logic here
                <?php endif; ?>
            <?php endforeach; ?>
        <?php endforeach; ?>

Some additional information: the array is contained in its own phtml file and included in the phtml files where it's necessary. I'm using PHP 7.2.24 and this is for a Magento 2 site. If there is a Magento 2 specific solution, that would be great.

Not sure what I've done wrong and why this isn't working. I know something's wrong, else I wouldn't get an error. Am I structuring the loops incorrectly? Using the keys wrong? Would a switch be a better idea here?

`$key` is a string like `id` or `images`. `$key[2]` is the third character of the key. What do you expect `$key[2][0]` to be? — Barmar, Jan 31 '20 at 22:03
What is `$cat`, and how are you trying to match that against the array element? — Barmar, Jan 31 '20 at 22:06
And `$value` is either a string like `Artist 01` or an array like `['engagement', 'wedding']`. What are you expecting `$value[2][1]` to be? — Barmar, Jan 31 '20 at 22:07
I'm guessing that what you really want is `if (in_array($cat, $artist['section']))` — Barmar, Jan 31 '20 at 22:09
I was expecting $key[2][0] to be the first element of its associated array, if it has one or whatever its string is. I'm trying to access the values of the keys. Probably need to call by $value instead of $key? — Marisa, Jan 31 '20 at 22:15
No, array keys are just numbers or strings, accessing them doesn't access the array. You need to use `$artist[$key]` to access the associated array element, but that's the same as `$value`. — Barmar, Jan 31 '20 at 22:17
But the array elements aren't always arrays. `$artist['id']` is a string, not an array. — Barmar, Jan 31 '20 at 22:17
The only element that's a multi-dimensional array is `images`. — Barmar, Jan 31 '20 at 22:18
You seem to be trying to filter the artists in some way, but it's not clear how. Could you give an example of `$cat` and which artists should be returned? — Barmar, Jan 31 '20 at 22:19
`$cat` is one of two things: wedding or engagement. I need certain artists to show on specific pages. Am I taking the wrong approach? — Marisa, Jan 31 '20 at 22:24

score 2 · Answer 1 · answered Jan 31 '20 at 22:32

You don't need to loop over the elements of the associative arrays. Just check for the category in the section element.

        <?php foreach ($bridal_artists as $artist): ?>
            <?php if(in_array($cat, $artist['section'])): ?>
               rest of logic here
            <?php endif; ?>
        <?php endforeach; ?>

The rest of the logic can use $artist['name'], $artist['featured_img'][$cat], etc.

PHP Getting "undefined offset" when Trying to Access Elements in Multidimensional Arrays

1 Answers1