a = [1,2]

for ctr in range(0,len(a)):
    print ctr
    if len(a) < 10:
        a.append(2)
	
while len(a) < 10:
    a.append(2)
	
a.extend([2] * (10 - len(a)))
	
a += [2] * (10 - len(a))
	
a += [2] * (10 - len(a))
	
a = [1,2]
while len(a) < 10:
    a.append(2)
	
>>> from itertools import chain, islice, repeat
>>> list(islice(chain(a, repeat(2)), 10))
[1, 2, 2, 2, 2, 2, 2, 2, 2, 2]