Workaround for isset, array_key_exists and !empty

Question

When coding php I try to avoid as many warnings as possible. There is one question that bugs me for quite some time now, regarding arrays.

When working with arrays and their values I often check for empty values first before I go to the "real work".

if(array_key_exists('bla', $array){
  if( !empty($array['bla']) {
    # do something
  }
}

My Question is:

This is a lot of code for just checking if I have values to work with. Is there some shorter way to check a value within an array that may or may not exist?

Answer 1

Don't use empty unless you are sure that's what you want:

Returns FALSE if var exists and has a non-empty, non-zero value. Otherwise returns TRUE.

The following things are considered to be empty:

• "" (an empty string)
• 0 (0 as an integer)
• 0.0 (0 as a float)
• "0" (0 as a string)
• NULL
• FALSE
• array() (an empty array)
• $var; (a variable declared, but without a value)

The manual doesn't explicitly list the "if var doesn't exist" cases, but here are a couple:

• $array['undeclaredKey'] (an existing array, but key not declared)
• $undeclaredVar; (a variable not declared)

Usually the array_key_exists check should suffice.

Answer 2

If you are checking for a non-empty value, then you can just use !empty($array['bla']).

You can also use isset($array['bla']), which returns false when: 1) key is not defined OR 2) if the value stored for the key is null. The only foolproof way to check if the array contains a key (even if its value is null) is to use array_key_exists().

The call to empty() is safe even if the key exists (behaves like isset()), so you don't have to protect it by the array_key_exists().

I am surprised this was not mentioned, but the shortest way fetch a value for a key without generating a warning/error is using the Error Control Operator:

// safely fetch from array, will return NULL when key doesn't exist
$value = @$array['bla'];

This allows you get the value for any key with the possibilty of its return value being null if the key does not exist.