如何读取python文本文件中的数字？答案

【问题标题】：How to read numbers in a text file for python?如何读取python文本文件中的数字？
【发布时间】：2016-09-06 00:26:35
【问题描述】：

我正在编写一个程序，我正在对存储在文件中的数字进行简单的计算。但是，它继续返回 ValueError。我应该在代码中更改什么或如何编写文本文件？

文件是：

def main():

    number = 0
    total = 0.0
    highest = 0
    lowest = 0

    try:
        in_file = open("donations.txt", "r")

        for line in in_file:
            donation = float(line)

            if donation > highest:
                highest = donation

            if donation < lowest:
                lowest = donation

            number += 1
            total += donation

            average = total / number

        in_file.close()

        print "The highest amount is $%.2f" %highest
        print "The lowest amount is $%.2f" %lowest
        print "The total donation is $%.2f" %total
        print "The average is $%.2f" %average

    except IOError:
        print "No such file"

    except ValueError:
        print "Non-numeric data found in the file."

    except:
        print "An error occurred."

main()

它正在读取的文本文件是

John Brown
12.54
Agatha Christie
25.61
Rose White
15.90
John Thomas
4.51
Paul Martin
20.23

【问题讨论】：

当它读入“John Brown”行时会发生什么？似乎您没有跳过所有其他行，这只是一个名称。但它第一次定义的最高值在哪里？
How to read numbers from file in Python?的可能重复

标签： python python-2.7

【解决方案1】：

如果您看不懂一行，请跳到下一行。

for line in in_file:
    try:
        donation = float(line)
    except ValueError:
        continue

稍微清理一下你的代码......

with open("donations.txt", "r") as in_file:
    highest = lowest = donation = None
    number = total = 0
    for line in in_file:
        try:
            donation = float(line)
        except ValueError:
            continue
        if highest is None or donation > highest:
            highest = donation

        if lowest is None or donation < lowest:
            lowest = donation

        number += 1
        total += donation

        average = total / number

print "The highest amount is $%.2f" %highest
print "The lowest amount is $%.2f" %lowest
print "The total donation is $%.2f" %total
print "The average is $%.2f" %average

【讨论】：