从零开始的Linux运维屌丝之路,资源免费分享平台   运维人员首选:简单、易用、高效、安全、稳定、社区活跃的开源软件
  • 首页
  • Python
  • 6、PythonWhile循环、dead loop、break、continue

6、PythonWhile循环、dead loop、break、continue

发布:蔺要红03-07分类: Python

Python快速入门:while循环

一、while循环

 
 dead loop(死循环):   while True
 continue   跳出本次循环,接着还执行后面的循环
 break  完全终止循环
  
 
打印1-100
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    print("loop:",count)
    count +=1
print(".......End............")   
[root@test01 /home]# python while1.py 
loop: 0
loop: 1
....
loop: 100
.......End............
 打印1-100之间的偶数
[root@test01 /home]# cat while2.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    if  count %2 == 0:
        print("loop:",count)
    count +=1
print(".......End............")
[root@test01 /home]# python while2.py 
loop: 0
loop: 2
loop: 4
.......
.......End............

  打印1-100、单不打印50且60-80取平方数、
 
if  条件
      pass    #如果条件成立则不执行  pass  新知识点
 
[root@test01 /home]# cat while3.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    if  count == 50:
        pass
    elif count >=60 and count <=80:
        print("loop",count*count)
    else:
        print("loop",count)
        
    count +=1
print(".......End............")
[root@test01 /home]# python  while3.py 
loop 0
loop 1
loop 2
..............
.......End...........
二、dead loop -------  while True:
[root@test01 /home]# cat while4.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while True:
    print("loop:",count)
    count +=1
三、break 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    print("loop:",count)
    if count == 5:
        break
    count +=1
print("........Een.........")
[root@test01 /home]# python while5.py 
loop: 0
loop: 1
loop: 2
loop: 3
loop: 4
loop: 5
........Een.........
不打印0
[root@test01 /home]# cat while8.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    count +=1
    print("loop:",count)
    if count == 5:
        break
print("........Een.........")
[root@test01 /home]# python while8.py 
loop: 1
loop: 2
loop: 3
loop: 4
loop: 5
........Een.........
        不打印0和5
[root@test01 /home]# cat while9.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    count +=1
    if count == 5:
        break
    print("loop:",count)
print("........Een.........")
[root@test01 /home]# python while9.py 
loop: 1
loop: 2
loop: 3
loop: 4
........Een.........
四、continue
[root@test01 /home]# cat while6.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    print("loop:",count)
    if count == 5:     #这里到5以后不会执行count +=1,所以一直是5,进入死循环
        continue 
    count +=1
print("........Een.........")
[root@test01 /home]# python while6.py 
loop: 0
loop: 1
loop: 2
loop: 3
loop: 4
loop: 5
loop: 5
loop: 5
.......
....
#无限循环5,死循环
把count +=1和打印调整一下位置
此时就会跳过5不打印、直到循环结束
[root@test01 /home]# cat while7.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    count +=1
    if count == 5:
        continue 
    print("loop:",count)
print("........Een.........")
[root@test01 /home]# python while7.py 
loop: 1
loop: 2
loop: 3
loop: 4
loop: 6
loop: 7
loop: 8
....
loop: 101
........Een.........

选择性打印
[root@test01 /home]# cat while10.py 
#!/usr/bin/python
#Author:linyaohng
count = 0
while count <=100:
    count +=1
    if count > 5 and count < 95:
        continue
    print("loop:",count)
print("........Een.........")
[root@test01 /home]# python while10.py 
loop: 1
loop: 2
loop: 3
loop: 4
loop: 5
loop: 95
loop: 96
loop: 97
loop: 98
loop: 99
loop: 100
loop: 101
........Een........

总结:当条件和要执行的命令位置不同时、执行结果不同
 
温馨提示如有转载或引用以上内容之必要,敬请将本文链接作为出处标注,如有侵权我会在24小时之内删除!

欢迎使用手机扫描访问本站