python怎么⽤while循环计算1+...+100_python:while循环语
句及练习题
while循环语句及练习题
Python 编程中 while 语句⽤于循环执⾏程序,即在某条件下,循环执⾏某段程序,以处理需要重复处理的相同任务。其基本形式为:while 判断条件: 执⾏语句…… 执⾏语句可以是单个语句或语句块。判断条件可以是任何表达式,任何⾮零、或⾮空(null)的值均为true。
当判断条件假 false 时,循环结束。
实例:
count = 0 while (count < 9): print ('The count is:', count) count = count + 1 print("Good bye!")
运⾏结果:
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
while 语句时还有另外两个重要的命令 continue,break 来跳过循环,continue ⽤于跳过该次循环,break 则是⽤于退出循环,此外”判断条件”还可以是个常值,表⽰循环必定成⽴,具体⽤法如下:
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
运⾏结果:
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
运⾏结果:
1 2 3 4 5 6 7 8 9 10
⽆限循环
如果条件判断语句永远为 true,循环将会⽆限的执⾏下去,如下实例:
var = 1 while var == 1 : # 该条件永远为true,循环将⽆限执⾏下去 num = input("Enter a number :") print ("You entered: ", num) print ("Good bye!")
Enter a number :3 You entered: 3 Enter a number :4 You entered: 4 Enter a number :5 You entered: 5 Enter a number :6 You entered: 6 Enter a number :7 You entered: 7 Enter a number :8 You entered: 8 Enter a number :100 You entered: 100 Enter a number :Traceback (most recent call last): File "c:/1.py", line 76, in # num = input("Enter a number :") KeyboardInterrupt
注意:以上的⽆限循环你可以使⽤ CTRL+C 来中断循环。
循环使⽤ else 语句
在 python 中,while … else 在循环条件为 false 时执⾏ else 语句块:
count = 0 while count < 5: print (count, " is less than 5") count = count + 1 else: print (count, " is not less than 5")
运⾏结果:
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
相关练习题
1.输出1,2,3,4,5,6,8,9,10
count = 1 while count <= 10:   if count == 7:     pass   else:     print(count)   count = count + 1python菜鸟教程100
2.输出1-100所有数的和
n = 1 m = 0 while n < 101:   m = m + n   n = n + 1 print(m)
3.输出100以内所有奇数
n = 1 while n < 101:   temp = n % 2   if temp == 0:     print(n)   else:     pass   n = n +1
4.输出1-2+3-4+5…..99所有数的和
n = 1 m = 0 while n < 100:   temp = n % 2   if temp == 0:     m = m - n   else:     m = m + n   n = n + 1 print(m)
参考资料:

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