这样写~
while 1: menu = raw_input('1: sum, 2: average,X: quit') if menu == 'X':break try:menu = int(menu) except:continue a = [] i = 0 if menu == 1: for i in range(0, 5): a += [raw_input('type a number')] b = 0 for n in a: b += float(n) print b elif menu == 2: for i in range(0, 5): a += [raw_input('type a number')] b = 0 for n in a: b += float(n) print b / 5.0 else: "please type correct number"