python 接收输入（字符串转数字）

n = input('please input a number:')

这样默认接收的是字符串，

如下代码就会报错：

n = input('please input a number:')
sum = 0
counter = 1
while counter <= n:
    sum = sum + counter
    counter += 1

print("1 到 %d 之和为: %d" % (n,sum))

 

改成如下：

n = int(input('please input a number:'))
sum = 0
counter = 1
while counter <= n:
    sum = sum + counter
    counter += 1

print("1 到 %d 之和为: %d" % (n,sum))