PHP Array Exercises : Get an array with the first key and value

Last update on May 30 2022 11:42:07 (UTC/GMT +8 hours)

PHP Array: Exercise-47 with Solution

Write a PHP function to get an array with the first key and value.

Sample Solution:

PHP Code:

<?php
function array_1st_element($my_array)
{
  list($k) = array_keys($my_array);
  $result  = array($k=>$my_array[$k]);
  unset($my_array[$k]);
  return $result;
}
$colors = array('c1'=>'Red','c2'=>'Green','c3'=>'Black');
print_r(array_1st_element($colors));
?>

Sample Output:

Array                                                       
(                                                           
    [c1] => Red                                             
)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP function to check whether all array values are strings or not.
Next: Write a PHP function to set union of two arrays.

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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