def f():
e=raw_input('enter number')
if e in range (12):
print 'co'
if e in range (12,20):
print 'co2'
if e in range (-10,0,1):
print 'co3'
f()
e 是一个字符串,你将它与一个 int 进行比较
do
def f():
e=int(raw_input('enter number'))
if e in range (12):
print 'co'
elif e in range (12,20):
print 'co2'
elif e in range (-10,0,1):
print 'co3'
f()