PHP Exercises: Deep flatten an given array
PHP: Exercise-79 with Solution
Write a PHP program to deep flatten an given array.
Sample Solution: -
PHP Code:
<?php
function deep_flatten($items)
{
$result = [];
foreach ($items as $item) {
if (!is_array($item)) {
$result[] = $item;
} else {
$result = array_merge($result, deep_flatten($item));
}
}
return $result;
}
$result = deep_flatten([1, [2], [[3], 4], 5, 6]);
print_r($result);
?>
Sample Output:
Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 [5] => 6 )
Flowchart:
PHP Code Editor:
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Previous: Write a PHP program to create a function that returns true for all elements of an array, false otherwise.
Next: Write a PHP program to create a new array with n elements removed from the left.
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PHP: Tips of the Day
How to Sort Multi-dimensional Array by Value?
Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:
Example:
function sortByOrder($a, $b) { return $a['order'] - $b['order']; } usort($myArray, 'sortByOrder');
Starting in PHP 5.3, you can use an anonymous function:
usort($myArray, function($a, $b) { return $a['order'] - $b['order']; });
And finally with PHP 7 you can use the spaceship operator:
usort($myArray, function($a, $b) { return $a['order'] <=> $b['order']; });
To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.
usort($myArray, function($a, $b) { $retval = $a['order'] <=> $b['order']; if ($retval == 0) { $retval = $a['suborder'] <=> $b['suborder']; if ($retval == 0) { $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder']; } } return $retval; });
If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual
Ref : https://bit.ly/3i77vCC
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