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up vote 2 down vote favorite
1

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.

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2  
What do you mean "failed," any errors? – Jonathan Sampson Feb 17 '10 at 14:43
1  
Are you sure there's a value in $array[4]? Because your syntax is correct - look elsewhere for the problem. – Erik Feb 17 '10 at 14:44
1  
Could you add some more details, for example which is the contents of $array ? – Dominik Feb 17 '10 at 14:44

5 Answers

up vote 4 down vote accepted

Your code seems to be fine, make sure that key you specify really exists in the array or such key has a value in your array eg:

$array = array(4 => 'Hello There');
print_r(array_keys($array));
// or better
print_r($array);

Output:

Array
(
    [0] => 4
)

Now:

$key = 4;
$value = $array[$key];
print $value;

Output:

Hello There
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1  
print_r($array) would be better - $array[4] may exist but be empty. – Erik Feb 17 '10 at 14:46
up vote 5 down vote 
$value = ( array_key_exists($key, $array) && !empty($array[$key]) ) 
         ? $array[$key] 
         : 'non-existant or empty value key';
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up vote 2 down vote

the simple way:

$value = key($array);
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doesn't that return the key instead of the value? – Dragon5689 Jul 6 at 11:35
up vote 1 down vote

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.

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up vote 0 down vote

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);
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