I want to use the values of my first array $selection (which are always numbers) as the keys for the other array $categories and output only the selected keys.
See code below, very new to php.
<?php
$selection = array('1', '4', '5');
$categories = array('fruit', 'bread', 'desert', 'soup', 'pizza');
$multiple = array_combine($selection, $categories);
print_r($multiple);
?>
so it should output something like:
Array ( [1] => fruit [4] => soup [5] => pizza )
Something like this works for you?
<?php
$selection = array('1', '4', '5');
$categories = array('fruit', 'bread', 'desert', 'soup', 'pizza');
$multiple = array();
foreach($selection as $value) {
if (isset($categories[$value - 1]))
$multiple[$value] = $categories[$value - 1];
}
}
print_r($multiple);
?>
isset($categories[$value] will always be false.
This should work for you:
Just get the array_intersect_key() from both arrays: $selection and $categories.
Note that since an array is index based 0 you have to go through your $selection array with array_map() and subtract one from each value to then use array_flip().
And at the end you can simply array_combine() the intersect of both arrays with the $selection array.
$result = array_combine($selection,
array_intersect_key(
$categories,
array_flip(
array_map(function($v){
return $v-1;
}, $selection)
)
));
output:
Array ( [1] => fruit [4] => soup [5] => pizza )