Remove blacklist keys from array in PHP

PhpArraysKey

Php Problem Overview


I have an associative array of data and I have an array of keys I would like to remove from that array (while keeping the remaining keys in original order -- not that this is likely to be a constraint).

I am looking for a one liner of php to do this.
I already know how I could loop through the arrays but it seems there should be some array_map with unset or array_filter solution just outside of my grasp.

I have searched around for a bit but found nothing too concise.

To be clear this is the problem to do in one line:

//have this example associative array of data
$data = array(
    'blue'   => 43,
    'red'    => 87,
    'purple' => 130,
    'green'  => 12,
    'yellow' => 31
);

//and this array of keys to remove
$bad_keys = array(
    'purple',
    'yellow'
);

//some one liner here and then $data will only have the keys blue, red, green

Php Solutions


Solution 1 - Php

$out = array_diff_key($data,array_flip($bad_keys));

All I did was look through the list of Array functions until I found the one I needed (_diff_key).

Solution 2 - Php

The solution is indeed the one provided by Niet the Dark Absol. I would like to provide another similar solution for anyone who is after similar thing, but this one uses a whitelist instead of a blacklist:

$whitelist = array( 'good_key1', 'good_key2', ... );
$output = array_intersect_key( $data, array_flip( $whitelist ) );

Which will preserve keys from $whitelist array and remove the rest.

Solution 3 - Php

This is a blacklisting function I created for associative arrays.

if(!function_exists('array_blacklist_assoc')){

    /**
     * Returns an array containing all the entries from array1 whose keys are not present in any of the other arrays when using their values as keys.
     * @param array $array1 The array to compare from
     * @param array $array2 The array to compare against
     * @return array $array2,... More arrays to compare against
     */

    function array_blacklist_assoc(Array $array1, Array $array2) {
        if(func_num_args() > 2){
            $args = func_get_args();
            array_shift($args);
            $array2 = call_user_func_array('array_merge', $args);
        } 
        return array_diff_key($array1, array_flip($array2));
    }
}

$sanitized_data = array_blacklist_assoc($data, $bad_keys);

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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionhackartistView Question on Stackoverflow
Solution 1 - PhpNiet the Dark AbsolView Answer on Stackoverflow
Solution 2 - PhpPmpr.irView Answer on Stackoverflow
Solution 3 - PhpTarranJonesView Answer on Stackoverflow