PHP Exercises: Get the index of the last element for which the given function returns a truth value
PHP: Exercise-82 with Solution
Write a PHP program to get the index of the last element for which the given function returns a truth value.
Sample Solution: -
PHP Code:
<?php
function find_last_Index($items, $func)
{
$keys = array_keys(array_filter($items, $func));
return array_pop($keys);
}
echo find_last_Index([1, 2, 3, 4], function ($n) {
return ($n % 2) === 1;
});
echo "\n";
echo find_last_Index([1, 2, 3, 4], function ($n) {
return ($n % 2) === 0;
});
?>
Sample Output:
2 3
Flowchart:
PHP Code Editor:
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Previous: Write a PHP program to get the last element for which the given function returns a truth value.
Next: Write a PHP program to group the elements of an array based on the given function.
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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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