PHP Explode Populate Keys Not Values

Question

Let's say you have a comma-delimited string:

$str = 'a,b,c';

Calling explode(',', $str); will return the following:

array('a', 'b', 'c')

Is there a way to explode such that the resulting array's keys, and not values, are populated? Something like this:

array('a' => null, 'b' => null, 'c' => null)

Nick · Accepted Answer · 2020-04-08 23:25:40Z

3

You can use array_fill_keys to use the output of explode as keys to a new array with a given value:

$str = 'a,b,c';
$out = array_fill_keys(explode(',', $str), null);
var_dump($out);

Output:

array(3) {
  ["a"]=>
  NULL
  ["b"]=>
  NULL
  ["c"]=>
  NULL
}

answered Apr 8, 2020 at 23:25

Nick

147k23 gold badges67 silver badges106 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Alberto · Accepted Answer · 2020-04-08 23:23:45Z

0

something like this:

$str = 'a,b,c';
$arr = [];
foreach ($explode(',', $str) as $key) {
    $arr[$key] = null;
}

not that pretty but it works

answered Apr 8, 2020 at 23:23

Alberto

13.1k3 gold badges31 silver badges72 bronze badges

Rakesh Jakhar · Accepted Answer · 2020-04-09 08:08:21Z

0

You can simply use explode with foreach

$res = [];
foreach(explode(",", $str) as $key){
  $res[$key] = null;
}
print_r($res);

answered Apr 9, 2020 at 8:08

Rakesh Jakhar

6,4082 gold badges13 silver badges20 bronze badges