Removing Array Values From One Array By Comparing Keys Of Another Array

Question

Suppose I have first array, $aAllCities as

Array
(
   [21] => London
   [9]  => Paris
   [17] => New York
   [3]  => Tokyo
   [25] => Shanghai
   [11] => Dubai
   [37] => Mumbai
)

And another array, $aNotSupportedCities as

Array
(
   [0] => 37
   [1] => 25
   [2] => 11
)

Is it possible to get an array like this ?

Array
(
   [21] => London
   [9]  => Paris
   [17] => New York
   [3]  => Tokyo
)

I want to remove array values of those keys that are present in other array

Pushpesh · Accepted Answer · 2012-04-19 07:41:10Z

up vote 1 down vote accepted

Try this:

$aAllCities = array_flip( $aAllCities );
$aAllCities = array_diff( $aAllCities, $aNotSupportedCities );
$aAllCities = array_flip( $aAllCities );

Hope this helps.

answered Apr 19 at 7:41

Pushpesh
1,343129

Thanks Pushpesh, exactly what I wanted – Sachyn Apr 19 at 7:45

feedback

Dan Lee · Answer 2 · 2012-04-19 07:33:53Z

up vote 0 down vote

$new = $aAllCities;
foreach($aNotSupportedCities as $id) {
  if (isset($new[$id]) {
    unset($new[$id]);
  }
}

answered Apr 19 at 7:33

Dan Lee
3,525619

feedback

JBRTRND · Answer 3 · 2012-04-19 07:35:42Z

up vote 2 down vote

foreach($aAllCities as $key => $value) {
    if(in_array($key,$aNotSupportedCities)) {
        unset($aAllCities[$key]); 
    }

}

answered Apr 19 at 7:35

JBRTRND
1,080211

feedback

SiGanteng · Answer 4 · 2012-04-19 07:40:14Z

up vote 0 down vote

$supportedCities = array_diff_key($aAllCities, array_values($aNotSupportedCities));

answered Apr 19 at 7:40

SiGanteng
17.3k11541

feedback

Spiritfyre · Answer 5 · 2012-04-19 07:46:21Z

The other answers are correct, but a smoother, faster way to do it is:
$supportedCities = array_diff_key($aAllCities, $aNotSupportedCities);

This will return all the values from $aAllCities that don't have keys in $aNotSupportedCities

Note, this compares the two arrays via their keys, so you will need to make your $aNotSupportedCities look like this:

Array
(
   [37] => something
   [25] => doesn't really matter
   [11] => It's not reading this
)

Best of luck.

5 Answers