Question

我必须编写一个程序，它将从文件中读取数据，将其转换为整数并总计金额。到目前为止，这就是我所拥有的。数据文件“numdata.txt”中的数字是：78,93,85,100,81,76,94,77。

def main():
total = 0

try:
    NumberFile = open('numdata.txt', 'r')

    for line in NumberFile:
        amount = float(line)
        total += amount
        print(format(total, ',.2f'))

except IOError:
    print('An error occurred trying to read the file.')

except ValueError:
    print('Non-numeric data found in the file.')

except:
    print('An error has occurred.')

finally:
     NumberFile.close()


main()

当我运行程序时，显示第一个数字（78），然后出现一个异常错误消息，奇怪的是它有时会有所不同。如果有人可以帮我指出正确的方向，我会很感激。我还是很新，所以请耐心等待。

我尝试过但尝试过但无法使循环正常工作，所以我最终选择了这条路线：

def main ():
infile = open('numdata.txt', 'r')
num1 = int(infile.readline())
num2 = int(infile.readline())
num3 = int(infile.readline())
num4 = int(infile.readline())
num5 = int(infile.readline())
num6 = int(infile.readline())
num7 = int(infile.readline())
num8 = int(infile.readline())
infile.close()
total = num1+num2+num3+num4+num5+num6+num7+num8
average = total/8
print('the total: ', total)
print('the average: ', average)

main（）的

它不漂亮，但它起作用我想lol

Answer 1

total = 0    

try:
    NumberFile = open('numdata.txt', 'r')

    for line in NumberFile:
        amount = float(line)
        total += amount
        print(format(total, ',.2f'))
except IOError:
    print('An error occurred trying to read the file.')
except ValueError:
    print('Non-numeric data found in the file.')
except:
    print('An error has occurred.')
finally:
    NumberFile.close()

发生异常是因为您在第一次迭代后立即关闭文件，导致您无法迭代其余部分。

将NumberFile.close()移动到finally子句可确保文件被关闭，无论出现什么问题。但是，在Python中读取/写入文件的更好方法是使用with keyword，这是一种确保相同内容的内置方法。

total = 0

with open('numdata.txt', 'r') as f:
    for line in f:
        try:
            total += float(line)
        except ValueError:
            print('Non-numeric data found in the file.')
            continue
        finally:
            print('{:.2f}'.format(total, ',.2f'))

Answer 2

您在第一次迭代中关闭文件NumberFile.close()没有正确缩进

使用异常从Python中的文件读取数据

2 个答案: