PHP - How to remove empty entries of an array recursively?

问题

I need to remove empty entries on multilevel arrays. For now I can remove entries with empty sub-arrays, but not empty arrays... confused, so do I... I think the code will help to explain better...

<?php

/**
 * 
 * This function remove empty entries on arrays
 * @param array $array
 */
function removeEmptysFromArray($array) {

    $filtered = array_filter($array, 'removeEmptyItems');
    return $filtered;
}

/**
 * 
 * This is a Callback function to use in array_filter()
 * @param array $item
 */
function removeEmptyItems($item) {

    if (is_array($item)) {
        return array_filter($item, 'removeEmptyItems');
    }

    if (!empty($item)) {
        return true;  
    }
}


$raw = array(
    'firstname' => 'Foo',
    'lastname'  => 'Bar',
    'nickname' => '',
    'birthdate' => array( 
        'day'   => '',
        'month' => '',
        'year'  => '',
    ),
    'likes' => array(
        'cars'  => array('Subaru Impreza WRX STi', 'Mitsubishi Evo', 'Nissan GTR'),
        'bikes' => array(),
    ),
);

print_r(removeEmptysFromArray($raw));

?>

Ok, this code will remove "nickname", "birthdate" but is not removing "bikes" that have an empty array.

My question is... How to remove the "bikes" entry?

Best Regards,

Sorry for my english...

回答1:

Try this code:

<?php
function array_remove_empty($haystack)
{
    foreach ($haystack as $key => $value) {
        if (is_array($value)) {
            $haystack[$key] = array_remove_empty($haystack[$key]);
        }

        if (empty($haystack[$key])) {
            unset($haystack[$key]);
        }
    }

    return $haystack;
}

$raw = array(
    'firstname' => 'Foo',
    'lastname'  => 'Bar',
    'nickname' => '',
    'birthdate' => array(
        'day'   => '',
        'month' => '',
        'year'  => '',
    ),
    'likes' => array(
        'cars'  => array('Subaru Impreza WRX STi', 'Mitsubishi Evo', 'Nissan GTR'),
        'bikes' => array(),
    ),
);

print_r(array_remove_empty($raw));

回答2:

I think this should solve your problem.

$retArray =array_filter($array, arrayFilter);

function arrayFilter($array) {
     if(!empty($array)) {
         return array_filter($array);
     }
}

回答3:

Here is my solution, it will remove exactly specified list of empty values recursively:

/**
 * Remove elements from array by exact values list recursively
 *
 * @param array $haystack
 * @param array $values
 *
 * @return array
 */
function array_remove_by_values(array $haystack, array $values)
{
    foreach ($haystack as $key => $value) {
        if (is_array($value)) {
            $haystack[$key] = array_remove_by_values($haystack[$key], $values);
        }

        if (in_array($haystack[$key], $values, true)) {
            unset($haystack[$key]);
        }
    }

    return $haystack;
}

You can use it like this:

$clean = array_remove_by_values($raw, ['', null, []]);

Note, it removes empty sub arrays if you pass [] as one of values.

回答4:

If you want array_filter to work recursively, you'll need to make sure that the subsequent calls may edit the deeper nested items of the array. Short: You'll need to pass it by reference:

function removeEmptyItems(&$item) {
    if (is_array($item) && $item) {
        $item = array_filter(&$item, 'removeEmptyItems');
    }

    return !!$item;
}

来源：https://stackoverflow.com/questions/7696548/php-how-to-remove-empty-entries-of-an-array-recursively

标签

php

arrays

array-filter