Question

我如何处理该部分而真正的for？我需要一个异常，告诉用户他需要输入一个数字（如果他不小心输入一个字符串）或一个值＆gt; 0.我尝试将nyear转换为int，因此会引发值错误，但这只会导致错误。

那你们怎么处理这个？

 def main():

    nyear = int(raw_input('Enter the years: '))    
    i = 0
    while True:
        try:
            intTarget = int(nyear)
        except ValueError:
            print 'Value needs to be a number and needs to be greater than 0'

        nyear = int(raw_input('Enter the years: '))

    for year in range(nyear):
        for month in range(12):
            rinch = float(raw_input('How many inches of rain: '))
            i += rinch 

        total = i
        tmonths = (month + 1) * (year + 1)
        ravg = total/tmonths
        print total, tmonths, ravg        
main()

Answer 1

将raw_input语句移至try块。
当用户输入有效的数字字符串时，使用break关键字来中断while循环。
将用户值从string转换为int。如果在类型转换期间出现任何异常，请再次询问。这将是代码的异常部分。
同时通过if循环检查输入数字是否大于0。

使用 e.g。

while True:
    try:
        nyear = int(raw_input('Enter the years: '))
        if nyear>0:
            break
        print 'Value needs to be a number and needs to be greater than 0.'
    except ValueError:
        print 'Value needs to be a number and needs to be greater than 0.'

输出：

Enter the years: w
Value needs to be a number and needs to be greater than 0.
Enter the years: -100
Value needs to be a number and needs to be greater than 0.
Enter the years: 2015

使用For计算一组值的程序

1 个答案: