# 1609.py

a=('Roma','Pisa','Milano','Trento')
print [x[0] for x in a]
# ['R', 'P', 'M', 'T']

print [x*x+3 for x in xrange(8)]
# [3, 4, 7, 12, 19, 28, 39, 52]

print [x+y for x,y in (3,2),(5,6),(1,9)]
# [5, 11, 10]

a=[3,5,1]; b=[2,6,9]
print [x+y for x,y in zip(a,b)]
# [5, 11, 10]