Python-控制流

 

if

#!/usr/bin/python

number=23
guess=int(input('Enter an interger:')) #input返回的结果是string类型，需要用int()转化为int类型

if guess == number:
    print('You guessed in.')
elif guess < number:
    print('No, it is a little higher than that')
else:
    print('No, it is a little lower than that')


print('Done')

while

#!/usr/bin/python

number = 23

while True:
    guess=int(input('Enter an integer:'))
    if guess==number:
        print('You guessed it')
        break
    elif guess<num:
        print('No, it is a little higher than that')
    else:
        print('No, it is a little lower than that')
else:#else下的statements是在while的条件为假时执行的，但如果有break,它就不会执行了
    print('The while loop is over')

print('Done')

for

#!/usr/bin/python

for i in range(1,5):
    print(i)
else:#else下的statements是在for循环结束后执行的，但如果有break,它就不会执行了
    print('The for loop is over')

range有三个参数，第三个参数在默认情况下为1，表示步长

range返回一个list,前闭后开，如:

range(1,5) 返回 [1,2,3,4]

range(1,5,2)返回 [1,3]

 

break和continue的用法与C++中一样