Python之‘’控制流‘’
一、if语句
格式:
i1 = 3 if i1 > 4 : print ( 'yes you are right' ) elif 0 < i1 < 4 : print ( 'im dont konw' ) else : print ( 'no you are wrong' ) |
注意if、elif以及else后面的(:)符号,我们通过它告诉Python下面跟着一个语句块。
二、while语句
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 lower than that' ) else : print ( 'no,it is a little higher than that ' ) else : print ( 'the while loop is over' ) print ( 'done' )<br><br>输出结果: |
enter an integer:22
no,it is a little lower than that
enter an integer:24
no,it is a little higher than that
enter an integer:23
congratulations,you guessed it
the while loop is over
done
注意:在Python2.x版本中输入使用的是raw_input而在Python3.x版本中输入使用的是input。并且后面都要跟冒号。
三、for循环
格式:for...in
for i in range ( 1 , 5 ): print (i) else : print ( 'the loop is over' ) 结果: C:\Python36\python.exe C: / Users / 蔡瑞 / 7.py 1 2 3 4 the loop is over Process finished with exit code 0 |
注意:range(1,5)只是输出1-4没有5。还有,else部分是可选的,如果包含else,它总是在for循环结束后执行一次,除非遇到break语句。
for循环在这个范围内递归,这就相当于把序列中的每个数(或对象)赋值给i,一次一个,然后以每个i的值执行这个程序块。
Programming is fun
When the work is done
if you wanna make your work also fun:
use Python
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