在python中使⽤while语句、输出字符串的奇数_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菜鸟教程python函数
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 + 1
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+
<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:
1.python while 循环语句 | 菜鸟教程:
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