python list of numbers converted to string incorrectly

For some reason, when I do the code...

def encode():
    result2 = []
    print result  
    for x in result:  
        result2 += str(x)  
    print result2

I get...

[123, 456, 789]
['1', '2', '3', '4', '5', '6', '7', '8', '9']

How do I get it to return ['123', '456', '789']?

Thanks!