Python While循环语句实例演示及原理解析

 #!/usr/bin/python
 count = 0
 while (count < 9):  print 'The count is:', count  count = count + 1 print "Good bye!"

The count is: 0
The count is: 1
The count is: 2
The count is: 3
The count is: 4
The count is: 5
The count is: 6
The count is: 7
The count is: 8
Good bye!

# continue 和 break 用法
i = 1
while i < 10:    i += 1   if i%2 > 0:   # 非双数时跳过输出
    continue
  print i     # 输出双数2、4、6、8、10

i = 1
while 1:      # 循环条件为1必定成立
  print i     # 输出1~10
  i += 1
  if i > 10:   # 当i大于10时跳出循环
    break

#coding=utf-8
#!/usr/bin/python

var = 1
while var == 1 : # 该条件永远为true，循环将无限执行下去
  num = raw_input("Enter a number :")
  print "You entered: ", num

print "Good bye!"

Enter a number :20
You entered: 20
Enter a number :29
You entered: 29
Enter a number :3
You entered: 3
Enter a number between :Traceback (most recent call last):
 File "test.py", line 5, in <module>
  num = raw_input("Enter a number :")
KeyboardInterrupt

#!/usr/bin/python

count = 0
while count < 5:
  print count, " is less than 5"
  count = count + 1
else:
  print count, " is not less than 5"

0 is less than 5
1 is less than 5
2 is less than 5
3 is less than 5
4 is less than 5
5 is not less than 5

#!/usr/bin/python
flag = 1
while (flag): print 'Given flag is really true!'
print "Good bye!"

#!/usr/bin/python
# -*- coding: UTF-8 -*-

import random
while 1:
  s = int(random.randint(1, 3))
  if s == 1:
    ind = "石头"
  elif s == 2:
    ind = "剪子"
  elif s == 3:
    ind = "布"
  m = raw_input('输入 石头、剪子、布,输入"end"结束游戏:')
  blist = ['石头', "剪子", "布"]
  if (m not in blist) and (m != 'end'):
    print "输入错误，请重新输入！"
  elif (m not in blist) and (m == 'end'):
    print "\n游戏退出中..."
    break
  elif m == ind :
    print "电脑出了： " + ind + "，平局！"
  elif (m == '石头' and ind =='剪子') or (m == '剪子' and ind =='布') or (m == '布' and ind =='石头'):
    print "电脑出了： " + ind +"，你赢了！"
  elif (m == '石头' and ind =='布') or (m == '剪子' and ind =='石头') or (m == '布' and ind =='剪子'):
    print "电脑出了： " + ind +"，你输了！"

 输入 石头、剪子、布,输入"end"结束游戏:石头
 电脑出了： 石头，平局！
 输入 石头、剪子、布,输入"end"结束游戏:石头  
 电脑出了： 剪子，你赢了！
 输入 石头、剪子、布,输入"end"结束游戏: