版本不同语法不同
1. print （‘’） print ‘’
2.input 与 raw_input
3代码（if和else用法）：
number = 23
guess = int(input ('Enter an integer:'))
if guess == number:
print ('Congratulations, you guessed it.')
print ("(but you do not win any prizes!)")
elif guess < number:
print ('No ,it is a little higher than that')
else :
print ('No, it is a little lower than that')
print ('Done')
4.while用法，可带一个else
number = 23
running = True
while running:
guess = int (input ('Enter an integer:'))
if guess == number:
print ('Congratulations , you guessed it.')
running = False
elif guess < number:
print ('No, it is a little higher than that')
else :
print ('No, it is a little lower than that')
else :
print (' The while loop is over.')
print ('Done')
5.for用法
for i in range (1, 5):
print （i）
else :
print （'The for loop is over ')
6. break 用法
while True:
s = input ('Enter something:')
if s == 'quit':
break
print ('Length of the string is', len(s))
print ('Done')
7.continue 用法
while True:
s = input ('Enter something:')
if s == 'quit':
break
if len(s) < 3:
continue
print (' input is of sufficient length')