How can I find the remainder when dividing 2 integers

[silverburgh.meryl at gmail.com]

I have a string array:
colors = ["#ff0000", "#00FF00", "#0000FF"]
colorIndex = 0;

and I want to loop thru each element of colors

 for str in strings:
 print colors[colorIndex++ % colors.length]


But i get an invalid syntax error when I execute the script:
    print colors[colorIndex++ % colors.length]
                              ^
SyntaxError: invalid syntax