Remove blacklist keys from array in PHP
PhpArraysKeyPhp 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);