[php] PHP how to get value from array if key is in a variable

I have a key stored in a variable like so:

$key = 4;

I tried to get the relevant value like so:

$value = $array[$key];

but it failed. Help.

As others stated, it's likely failing because the requested key doesn't exist in the array. I have a helper function here that takes the array, the suspected key, as well as a default return in the event the key does not exist.

    protected function _getArrayValue($array, $key, $default = null)
    {
        if (isset($array[$key])) return $array[$key];
        return $default;
    }

hope it helps.

$value = ( array_key_exists($key, $array) && !empty($array[$key]) ) 
         ? $array[$key] 
         : 'non-existant or empty value key';

It should work the way you intended.

$array = array('value-0', 'value-1', 'value-2', 'value-3', 'value-4', 'value-5' /* … */);
$key = 4;
$value = $array[$key];
echo $value; // value-4

But maybe there is no element with the key 4. If you want to get the fiveth item no matter what key it has, you can use array_slice:

$value = array_slice($array, 4, 1);