PHP Store Key Value from Associative Array into Simple Array - php

Question

I'm having trouble wrapping my head around this, any help would be GREAT...
I have an array $stores that is structured like so:
Array
(
[0] => Array
(
[id] => 123
[name] => 'Store A'
)
[1] => Array
(
[id] => 345
[name] => 'Store B'
)
[2] => Array
(
[id] => 567
[name] => 'Store C'
)
[3] => Array
(
[id] => 789
[name] => 'Store D'
)
)
I want to extract the 'id' values from this array into a simple array that looks this:
$simple = array(123,345,567,789);

Answer 1

If you use php 5.5+, array_column() is quite useful :
$simple = array_column($yourarray,'id');
http://php.net/array_column

Answer 2

Calimero definitely had the best answer for PHP 5.5+, but if you want the same functionality in prior versions, check this repository: https://github.com/ramsey/array_column . It is written by PHP 5.5 array_column creator itself.

Answer 3

If you can't use array_column, you can use array_map:
$names = array(
array('id' => 123, 'name' => 'A'),
array('id' => 456, 'name' => 'B'),
array('id' => 789, 'name' => 'C'),
);
$ids = array_map(function ($name) {
return $name['id'];
}, $names);
var_dump($ids);
// output
array(3) {
[0] => int(123)
[1] => int(456)
[2] => int(789)
}

Answer 4

You can simply use the following syntax if you are unable to upgrade the php version. In that kind of case use if (!function_exists('array_column')) to prevent re-declaration of the function which may occur on version upgrade.
Description From php.net
array_column() returns the values from a single column of the array, identified by the column_key. Optionally, you may provide an index_key to index the values in the returned array by the values from the index_key column in the input array.
/* Function array_column equivalent to php's array_column */
if (!function_exists('array_column'))
{
function array_column(array $array, $column_key, $index_key = NULL)
{
if (isset($array))
{
$return = array();
foreach ($array as $a)
{
if ($index_key)
{
if (!isset($a[$index_key]))
{
return array();
}
else
{
$return[$a[$index_key]] = $a[$column_key];
}
}
else
{
$return[] = $a[$column_key];
}
}
return $return;
}
return array();
}
}
Here are some examples taken from PHP.NET
<?php
$records = array(
array(
'id' => 2135,
'first_name' => 'John',
'last_name' => 'Doe',
),
array(
'id' => 3245,
'first_name' => 'Sally',
'last_name' => 'Smith',
),
array(
'id' => 5342,
'first_name' => 'Jane',
'last_name' => 'Jones',
),
array(
'id' => 5623,
'first_name' => 'Peter',
'last_name' => 'Doe',
)
);
$first_names = array_column($records, 'first_name');
print_r($first_names);
?>
It will give below output:
Array
(
[0] => John
[1] => Sally
[2] => Jane
[3] => Peter
)
Get column of last names from recordset, indexed by the "id" column
<?php
$last_names = array_column($records, 'last_name', 'id');
print_r($last_names);
?>
It will give you output as below:
Array
(
[2135] => Doe
[3245] => Smith
[5342] => Jones
[5623] => Doe
)

Answer 5

$simple = [];
foreach ($stores as $store){
$simple[] = $store['id'];
}