how to iterate a specific number of times on a for loop list?

Hi,

I have a FOR loop list consisting of 15 rows. But how can I make this FOR loop list stop at row 5?

# http://www.doughellmann.com/PyMOTW/itertools/index.html#module-itertools

from itertools import islice, count

j = 1

lines = open('machines.txt', 'r').readlines()

# while (j > 0):

for line in lines:
    print '%2s        %s' % (j, line)
    j = j+1

I tried Doug Hellmann's islice() example but couldn't figure out how to integrate this into my code?

from itertools import *

print 'Stop at 5:'
for i in islice(count(), 5):
    print i