How to split string into individual characters?

So, i would like to make:

''Hey dude!''

into

''HeY DUdE'' (or similar)

using a script.

Using my pre-existant knowledge of how to do this in python, for the first step, i tried splitting a string into characters, and place them into an array:

text = 'Hey dude!'
tt = {}
for i = 1,#text do
    table.insert(tt, text[i])
end

for i = 1,#tt do --Debug
    print(tt[i])
end

However, this script will not fill the list.

Any ideas on how to make this work would be great. Thanks.