Using array_map instead of foreach in PHP

Question

I have the following array:

$inventory = [
    'Apples' => ['Golden Delicious', 'Granny Smith','Fuji'],
    'Oranges' => ['Valencia', 'Navel', 'Jaffa']
];

What I would like to end up with is an array with the following:

['Apples','Oranges']

I can do:

$fruits = [];
foreach ($inventory as $key => $value) {
    $fruits[] = $key;
}

I am trying to educate myself on the use array_map, I tried:

$fruits[] = array_map('fruitTypes', $inventory);

function fruitTypes($item) {
    echo key($item)."\n";
    echo array_key_first($item)."\n";
    echo $item[0]."\n";
    //return something that will give me 'Apples' followed by 'Oranges'
}

But I am getting this:

0
0
Golden Delicious
0
0
Valencia

Any ideas?

you need to use array_keys in conjuction with array map. the keys in array map is not accessible out of the box — Kevin
– Kevin, Commented Oct 21, 2021 at 2:53

Crisoforo Gaspar · Accepted Answer · 2021-10-21 02:39:19Z

2

You can use array_keys, which returns an array of the keys of an associative array.

$fruits = array_keys( $inventory )

answered Oct 21, 2021 at 2:39

Crisoforo Gaspar

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2 Comments

EastsideDev Over a year ago

Yes, but I am trying to learn about array_map, the example I gave is a simple case. I am trying to figure out how to extract each key though a callback function.

Crisoforo Gaspar Over a year ago

You can't use array_map as it does not provide the keys on the parameter of the callback function so you might want to take a look at array_walk instead.

Newish · Accepted Answer · 2021-10-21 02:46:23Z

0

Array Keys would do this, not array Map.

<?php

inventory = [
    'Apples' => ['Golden Delicious', 'Granny Smith','Fuji'],
    'Oranges' => ['Valencia', 'Navel', 'Jaffa']
];

$keys = array_keys( $inventory );

var_dump($keys);

Would produce:

array(2) {
  [0]=>
  string(6) "Apples"
  [1]=>
  string(7) "Oranges"
}

answered Oct 21, 2021 at 2:46

Newish

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