# lista kwadratów liczb od 0 do 9
[x**2 for x in range(10)]

# lista dwuwymiarowa [20,40] o wartościach a
a = int(raw_input("Podaj liczbę całkowtią: "))
[[a for y in xrange(20)] for x in xrange(40)]

# lista krotek (x, y), przy czym x != y
[(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]

f = open('test.txt', 'r')
for line in f:
    print line[0]
f.close()

with open("text.txt", "r") as txt:
    for line in txt:
        print line

for line in open('test.txt', 'r'):
    print line[0]