Accessing String contents

[meino.cramer@...]

Hi,

from a string in a table like this

    a={}
    a[1]="hello"

I want to access/retrieve the n-th character.

Somewhere I read about, that in lua everything is a table,
therefore I thought that

    =a[1][1]

would gives me "h" instead of an error. 

But this may be thought too C-ish... ;)

I scanned through the String Tutorial, the String Library Tutotrial
and the online version of Programming Lua and found nothing what seems
appropiate to me...but I am sure that's due to me.... :)

What is the most cheapest (in terms of performance and programming
overhead) way to access the n-th character of a string which stored
at a certain index in a table?

Thank you very much in advance for any help!
Best regards,
mcc