Undefined array key in nested array loop php

Question

I have been trying but i don't know how i can create something like that dynamically without this warnings, $response[$item[0]][$item[1]] += 1; that line is where i struggling to run without php warnings of undefined, thats my code

   $data = [
        'blue-XG',
        'white-PP',
        'blue-XG',
        'black-PP',
        'black-M',
        'white-G',
        'black-G',
        'vermelho-M',
        'black-GG',
        'blue-P',
        'black-GG',
        'blue-XG',
    ];
    sort($data);
    
    $formatted = array_map(fn($c) => explode('-', $c), $data);
    
    $response = [];
    foreach ($formatted as $item) {
        $response[$item[0]][$item[1]] += 1;
    }
    
    print_r($response);

and that is my output

➜ /tmp php product.php
PHP Warning:  Undefined array key "black" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "G" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "GG" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "M" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "PP" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "blue" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "P" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "XG" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "vermelho" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "M" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "white" in /tmp/product.php on line 34
PHP Warning:
PHP Warning:  Undefined array key "black" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "G" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "GG" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "M" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "PP" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "blue" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "P" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "XG" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "vermelho" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "M" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "white" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "G" in /tmp/product.php on line 34
PHP Warning:  Undefined array key "PP" in /tmp/product.php on line 34
Array
(
    [black] => Array
        (
            [G] => 1
            [GG] => 2
            [M] => 1
            [PP] => 1
        )

    [blue] => Array
        (
            [P] => 1
            [XG] => 3
        )

    [red] => Array
        (
            [M] => 1
        )

    [white] => Array
        (
            [G] => 1
            [PP] => 1
        )

I want to achieve this output, my output kind of works, but with php warnings, i just want to fix the undefined array keys in the output block

[
    'black' =>  [
        'PP' => 1,
        'M' => 1,
        'G' => 1,
        'GG' => 2
    ],
    'white' => [
        'PP'=> 1,
        'G' => 1
    ],
    'red' => [
        'M' => 1
    ],
    'blue' => [
        'XG' => 3,
        'P' => 1
    ]
]

Perhaps you should share what kind of output you're trying to achieve. Right now it's hard to see what you're attempting at that line of code. — jszobody
– jszobody, Commented Feb 11, 2022 at 14:29

meewog · Accepted Answer · 2022-02-11 14:33:19Z

4

<?php

$data = [
    'blue-XG',
    'white-PP',
    'blue-XG',
    'black-PP',
    'black-M',
    'white-G',
    'black-G',
    'vermelho-M',
    'black-GG',
    'blue-P',
    'black-GG',
    'blue-XG',
];
sort($data);

$formatted = array_map(fn($c) => explode('-', $c), $data);

$response = [];
foreach ($formatted as $item) {
    // if $response does not have $item[0] key, create it
    if (!isset($response[$item[0]])) {
        $response[$item[0]] = [];
    }

    // if $response does not have $item[0][$item1] value, create it and add 0 value
    if (!isset($response[$item[0]][$item[1]])) {
        $response[$item[0]][$item[1]] = 0;
    }

    ++$response[$item[0]][$item[1]];
}

print_r($response);

you can check isset on usage.

The problem is on first iteration of each index of the colours, they do not exist and needs to be created first.

answered Feb 11, 2022 at 14:33

meewog

1,7401 gold badge22 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Undefined array key in nested array loop php

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related