PHP Exercises: Create a new array with n elements removed from the left

Last update on May 30 2022 11:45:07 (UTC/GMT +8 hours)

PHP: Exercise-80 with Solution

Write a PHP program to create a new array with n elements removed from the left.

Sample Solution: -

PHP Code:

<?php
function drop_from_left($items, $n = 1)
{
    return array_slice($items, $n);
}
print_r(drop_from_left([1, 2, 3])); 
print_r(drop_from_left([1, 2, 3, 4], 2));

?>

Sample Output:

Array
(
    [0] => 2
    [1] => 3
)
Array
(
    [0] => 3
    [1] => 4
)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to deep flatten an given array.
Next: Write a PHP program to get the last element for which the given function returns a truth value.

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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