How to access array data using a variable

[NachoDogMtl]

This is really starting to get me mad... I've tried everything.

Here's a simplified example of what I'm trying to do:

$mydata = array('0'=>'somedata', '1'=>'somemoredata', '2'=>'againdata');

//Say I'm getting 0, 1 or 2 from a form on the previous page:
$a = $_POST['number'];

//Then depending on the value of $a, I want to access the data in the array

echo $mydata['$a'];

The trouble is that I know I'm doing something wrong with that last lign, I just don't know what the syntax is!

Please help.
Thanks,
Alex

[Roger_Ramjet]

Well, if $a is really an integer then it does not need the quotes around it.

if (is_finite($a) {
echo $mydata[$a];
}