PHP delete array value

Question

I have 2 arrays.

<?php
$array1 = array('id' => 1, 'email' => '[email protected]' , 'name' => 'john' );
$array2 = array('id', 'email');

i am having trouble writing a code to unset the key value pair from array1 that is not from array 2.

The problem with this is unlike most examples, my array2 does not have a format of a key value pair but only key.

How do i go about removing things from array1 that is not specified in array2.

my current code is not working

foreach ($array1 as $key => $value) {
if (array_search($key, $array2)===false) {
 unset($key);
}
}

Any string keys or values in your array should be enclosed in quotes so john should be 'john' — Pattle
– Pattle, Commented Apr 1, 2014 at 8:27

Alma Do · Accepted Answer · 2014-04-01 09:21:24Z

6

Use array_diff_key() to leave values which are not in second array:

$array1 = array('id'=>1, 'email'=> 'email' , 'name'=>'john' );
$array2 = array('id','email');

$result = array_diff_key($array1, array_flip($array2));

Or, if you want to change first array:

$array1 = array_diff_key($array1, array_flip($array2));

Edit (misunderstanding)

Use array_intersect_key() to leave values which are in second array:

$array1 = array_intersect_key($array1, array_flip($array2));

edited Apr 1, 2014 at 9:21

answered Apr 1, 2014 at 8:25

Alma Do

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9 Comments

Alma Do Over a year ago

Please, leave a comment if dv - that would be appreciated

Shankar Narayana Damodaran Over a year ago

Maybe they did since the answer is not complete.

Alma Do Over a year ago

And I edited it also - because no sense in loop if we can avoid it (and write directly to first array)

Alma Do Over a year ago

array_flip() is needed because your second array contains values, not keys. It's like [0=>'id', 1=>'email'] so it's keys are 0 and 1 while for array_diff_key() you need to pass array with keys to get difference

Jeremiah Lim Over a year ago

One more thing is that as I Can Has Cheezburger mentioned, i want to output items that are specified in $array2. So the function used should be array_intersect_key instead of array_diff_key

|

AyB · Accepted Answer · 2014-04-01 08:38:13Z

5

You are doing it right, just that your way of unset is incorrect:

unset($key);

should be

unset($array1[$key]);

Demo

answered Apr 1, 2014 at 8:38

AyB

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Comments

Uriziel · Accepted Answer · 2014-04-01 09:48:22Z

0

You have to unset the element by its index (starting from 0) For example unset($array2[1]); will remove the 'email' element.

So in Your case it should be: unset($array1[$key]);

edited Apr 1, 2014 at 9:48

answered Apr 1, 2014 at 8:24

Uriziel

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