PHP remove empty, null Array key/values while keeping key/values otherwise not empty/null

Question

I have an array thats got about 12 potential key/value pairs. That are based off a _POST/_GET

The keys are not numeric as in 0-n, and I need to retain the keys with there values where applicable. My issue is I know that on occasion a key will be passed where the value is null, empty, or equal to ''. In the event thats the case I want to trim out those keys before processing my array. As running down the line without something there is going to break my script.

Now a while back I either made or found this function (I don't remember which its been in my arsenal for a while, either way though).

function remove_array_empty_values($array, $remove_null_number = true)
    {
        $new_array = array();
        $null_exceptions = array();
        foreach($array as $key => $value)
        {
            $value = trim($value);
            if($remove_null_number)
            {
                $null_exceptions[] = '0';
            }
            if(!in_array($value, $null_exceptions) && $value != "")
            {
                $new_array[] = $value;
            }
        }
        return $new_array;
    }

What I would love to do is very similar to this, however this works well with arrays that can have n-n key values and I am not dependent upon the key as well as the value to determine whats what where and when. As the above will just remove everything basically then just rebuilt the array. Where I am stuck is trying to figure out how to mimic the above function but where I retain the keys I need.

Unless I misunderstand the requirement, that is the exact function of array_filter() — Michael Berkowski
– Michael Berkowski, Commented Mar 5, 2012 at 14:14

Tomas Gonzalez · Accepted Answer · 2015-06-08 20:14:06Z

31

If you want a quick way to remove NULL, FALSE and Empty Strings (""), but leave values of 0 (zero), you can use the standard php function strlen as the callback function:

// removes all NULL, FALSE and Empty Strings but leaves 0 (zero) values
$result = array_filter( $array, 'strlen' );

Source: http://php.net/manual/en/function.array-filter.php#111091

answered Jun 8, 2015 at 20:14

Tomas Gonzalez

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1 Comment

Marcio Duarte Over a year ago

Note: this doesn't work on multidimentional arrays.

Aleks G · Accepted Answer · 2012-03-05 14:18:13Z

27

If I understand correctly what you're after, you can use array_filter() or you can do something like this:

foreach($myarray as $key=>$value)
{
    if(is_null($value) || $value == '')
        unset($myarray[$key]);
}

answered Mar 5, 2012 at 14:18

Aleks G

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5 Comments

George Cummins Over a year ago

You may wish to use if ( empty( $value ) ) to be more comprehensive.

Aleks G Over a year ago

@GeorgeCummins: agree, that's an option. Internally, it does the same thing though - right?

George Cummins Over a year ago

empty() is more comprehensive because it also checks for 0, false, "0", 0.0, empty arrays, etc. It is also a little simpler to read and maintain.

Aleks G Over a year ago

@GeorgeCummins Fair enough, however this is not what he wants: he states that he only wants to filter out nulls and empty strings.

George Cummins Over a year ago

@chris said: "where the value is null, empty, or equal to '' ." Since he specifically said "empty" and didn't say "empty string" I assumed my interpretation was correct. Perhaps a little clarification from from the asker would be helpful.

Jon · Accepted Answer · 2012-03-05 14:13:07Z

array_filter is a built-in function that does exactly what you need. At the most you will need to provide your own callback that decides which values stay and which get removed. The keys will be preserved automatically, as the function description states.

For example:

// This callback retains values equal to integer 0 or the string "0".
// If you also wanted to remove those, you would not even need a callback
// because that is the default behavior.
function filter_callback($val) {
    $val = trim($val);
    return $val != '';
}

$filtered = array_filter($original, 'filter_callback');

marc_s · Accepted Answer · 2024-09-11 20:32:04Z

1

If you want to remove null, undefined, '', 0, '0', but don't remove string ' '

$result = array_filter( $array, 'ucfirst' );

edited Sep 11, 2024 at 20:32

marc_s

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answered Oct 30, 2020 at 6:56

Nguyễn Văn Hoàng

111 bronze badge

Comments

Pravin Kumar · Accepted Answer · 2022-03-09 06:46:19Z

0

Filtering the array for PHP 7.4 and above use this

// Filtering the array
$result = array_filter($array, fn($var) => ($var !== NULL && $var !== FALSE && $var !== ""));

answered Mar 9, 2022 at 6:46

Pravin Kumar

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Comments

Anwarul Islam · Accepted Answer · 2018-02-11 12:12:24Z

-3

use +1 with your key variable to skip null key in array

foreach($myarray as $key=>$value)
{
    echo $key+1; //skip null key
}

answered Feb 11, 2018 at 12:12

Anwarul Islam

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