How to convert this* string:
$arrKeys = ['lev1', 'lev2', 'lev3'];
$val = 'foo';
In to the following array:
Array
(
[lev1] => Array
(
[lev2] => Array
(
[lev3] => foo
)
)
)
*Number of array keys may vary. Each array key except the last one represents Array.
Thank you!
No recursion necessary:
$arrKeys = array_reverse(['lev1', 'lev2', 'lev3']);
$val = 'foo';
$result = $val;
foreach ($arrKeys as $key) {
$result = [$key => $result];
}
print_r($result);
// Array
// (
// [lev1] => Array
// (
// [lev2] => Array
// (
// [lev3] => foo
// )
//
// )
//
// )
Just build the array from the inside out.
Here's one way you can do it with a recursive function. This is my personal favourite because it has very good readability.
function nest(array $keys, $value) {
if (count($keys) === 0)
return $value;
else
return [$keys[0] => nest(array_slice($keys, 1), $value)];
}
$result = nest(['key1', 'key2', 'key3'], 'foo');
print_r($result);
// Array
// (
// [key1] => Array
// (
// [key2] => Array
// (
// [key3] => foo
// )
// )
// )
Or another way you can do it using array_reduce. This way is also quite nice but there's a little added complexity here because the array of keys has to be reversed first.
function nest(array $keys, $value) {
return array_reduce(array_reverse($keys), function($acc, $key) {
return [$key => $acc];
}, $value);
}
$result = nest(['key1', 'key2', 'key3'], 'foo');
print_r($result);
// Array
// (
// [key1] => Array
// (
// [key2] => Array
// (
// [key3] => foo
// )
// )
// )
Both solutions work for any number of keys. Even if $keys is an empty array
nest([], 'foo'); //=> 'foo'
This is a pretty similar approach to the other iterative answer, but pops values off the end of the $arrKeys array rather than reversing it at the beginning.
$result = $val; // start with the innermost value
while ($level = array_pop($arrKeys)) {
$result = [$level => $result]; // build out using each key as a new level
}
