PHP in_array_keys-like function

Question

Is there a similar function like in_array() but that can check array keys, instead of values?

-1 because the php.net page for in_array links to array_key_exists — user142162
– user142162, Commented Jun 24, 2011 at 22:54

Alexander Gessler · Accepted Answer · 2011-06-24 22:46:25Z

8

It is named array_key_exists.

answered Jun 24, 2011 at 22:46

Alexander Gessler

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5 Comments

GolezTrol Over a year ago

Good answer, great function. :)

Alex Over a year ago

but it's not the same, you can only check a string

user142162 Over a year ago

@Alex: From PHP.net: key can be any value possible for an array index.

Alex Over a year ago

so can I use array_key_exists(array('abc', 'xyz'), array('abc' => 343, 'xyz' => 3434, 'def' => 343434) ?

user456814 Over a year ago

@Alex the documentation doesn't say, so I'm assuming no, but you could always just use the function in a for loop to get the same result.

Community · Accepted Answer · 2017-05-23 12:22:10Z

4

Based on the comment you left on @Alexander Gessler's answer, here's a small function you could use:

function array_keys_exist(array $keys, array $array)
{
  // Loop through all the keys and if one doesn't exist, return false.
  foreach ( $keys as $key )
    if ( ! array_key_exists($key, $array) )
      return false;

  // All keys were found.
  return true;
}

if ( array_keys_exist(array('abc', 'xyz'), array('abc' => 343, 'xyz' => 3434, 'def' => 343434)) )
  echo 'All keys exist!';

The function above called array_keys_exist loops through all the keys in the keys array calling PHP's array_key_exists function and if a key isn't found the function returns false (or true if all the keys were found in the array).

edited May 23, 2017 at 12:22

CommunityBot

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answered Jun 24, 2011 at 23:25

Francois Deschenes

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Comments

Jasper · Accepted Answer · 2011-06-24 22:47:26Z

2

There happens to be just that:

array_key_exists()

Found on the php docs: http://php.net/manual/en/function.array-key-exists.php

answered Jun 24, 2011 at 22:47

Jasper

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