PHP checking for array key or using default value

Question

I currently use this code pattern fairly frequently

if(array_key_exists('possible_key', $array)) {
    $my_variable = $array['possible_key'];
} else {
    $my_variable = 'my default value';
}

Is there a better way to be writing this?

Answer 1

One quick change you can do is making use of ternary operator instead of writing if else block.

$my_variable = array_key_exists('possible_key', $array) 
               ? $array['possible_key'] 
               : 'my default value';

Answer 2

I would prefer to keep it simple and not to use if else. Just assign it the default value, and change only when the condition meets.

$my_variable = 'my default value';
if(array_key_exists('possible_key', $array)) $my_variable = $array['possible_key'];

Answer 3

class ArrayHelper {

    public static function KeyExists($source, $key) {
        return isset($source[$key]) || array_key_exists($key, $source);
    }

    public static function GetValueOrDefault($source, $key, $default) {
        return self::KeyExists($source, $key) ? $source[$key] : $default;
    }

}

This is from my library it's similar to the other solutions but it's using a little hack: the array_key_exists() is a slow function so i execute first an isset() 'function' and if it's says "yes, it exists" then i don't have to execute the array_key_exists() function. The reason why isset() is not enough is the isset() will return FALSE if the key exists but the value is NULL.

Answer 4

Is there an atomic way to check if the value exists by a key AND return the value, so there will be just one query to the array? I think that this was the original idea of the author of the question. In a very large array, all examples here have shown essentially too lookup: for example array_key_exists('possible_key', $array) ? $array['possible_key'] etc...

A better way would be a single operation with the array that would not give a PHP run time warning in the key does not exist.

Answer 5

Untested code here as I don't have access to my dev machine, but taking Sky's ternary suggestion above and simplifying it (one empty() call is faster than an array_key_exists (see https://stackoverflow.com/questions/6884609/array-key-existskey-array-vs-emptyarraykey)

$var = empty($array['possible_key']) ? 'default value' : $array['possible_key']; 

Answer 6

I prefer to use use isset and make little refactor and wrap that code to function/method

function defaultize( $array_var ,$defaul_val ){
 if(isset($array_var)) {
    $ret = $array_var;
 } else {
    $ret = 'my default value';
 }
 return $ret;
}

and then use in code

$my_variable = defaultize($array['possible_key'],'my default_value' );
$my_variable2 = defaultize($array['possible_key2'],'my default_value2' );