PHP - 如何递归删除数组的空条目？

Question

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...

Answer 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));

Answer 2

I think this should solve your problem.

$retArray =array_filter($array, arrayFilter);

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

Answer 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.

Answer 4

Recursively clear multidimensional array of empty'ish items:

final class ArrayCleaner
{
    public static function clean(array $value): array
    {
        foreach ($value as $k => $v) {
            if (\is_array($v)) {
                $value[$k] = self::clean($v);

                if (0 == \count($value[$k])) {
                    unset($value[$k]);
                }
            } elseif (empty($v)) {
                unset($value[$k]);
            }
        }

        return $value;
    }
}

Unit test:

final class ArrayCleanerTest
{
    public function testItCleans(): void
    {
        $input = [
            'empty_string_to_remove' => '',
            'empty_int_to_remove' => 0,
            'empty_string_number_to_remove' => '0',
            'value_to_keep' => 5,
            'empty_array_to_remove' => [],
            'empty_array_of_empty_arrays_to_remove' => [
                'one' => [],
                'two' => [],
                'three' => [false, null, '0'],
            ],
            'array_to_keep_1' => [
                'value' => 1,
            ],
            'array_to_keep_2' => [
                'empty_to_remove' => [],
                'array_to_keep' => ['yes'],
            ],
        ];

        $expected = [
            'value_to_keep' => 5,
            'array_to_keep_1' => [
                'value' => 1,
            ],
            'array_to_keep_2' => [
                'array_to_keep' => ['yes'],
            ],
        ];

        $this->assertEquals($expected, ArrayCleaner::clean($input));
    }
}

Working proof of concept at 3v4l.org

Answer 5

My function:

function removeEmptyItems($item)
{
    if (is_array($item)) {
        $item = array_filter($item, 'removeEmptyItems');
    }
    return !empty($item);
}

$nonEmpty = array_filter($raw, 'removeEmptyItems');

Answer 6

array_filter(explode('/', '/home/teste sdsd/   /'), 'trim');
//Result
[
     1 => "home",
     2 => "teste sdsd",
]

//-----------
array_filter(explode('/', '/home/teste sdsd/   /'), 'strlen')
//Result
  [
     1 => "home",
     2 => "teste sdsd",
     3 => "   ",
   ]

Answer 7

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;
}