Need help with concatenating variables

I’m having trouble getting the following to work:

I have declared an array “playlistArray” which will hold a series of track names (for an mp3 player.)
I have declared a URLVariable “playlistVariables” which loads the data from an external text file.
If I brute-force assign values from playlistVariables to playlistArray, everything works fine:
playlistArray[0] = playlistVariables.track0;
If I test this with trace(playlistArray[0]) I get the track name I am looking for.

But obviously I don’t want to brute-force assign all those values, I want to use a “for” loop:

for (var i:int = 0; i<maxTracks; i++) {
playlistArray* = [“playlistVariables.track”+(i)];

When I do this, I end up with playlistArray[0] containing the string “playlistVariables.track0” rather than the value of playlistVariables.track0.

What am I doing wrong?