使用 sum 时如何避免出现不受支持的类型错误

Question

我是 python 的新手，我试图从文件中获取数据，将其放入列表中，然后获取每一行的总和。我尝试删除除 int 和 float 之外的任何内容的列表，并确保文件只有数字。如果有人可以帮助我，我将非常感激。感谢阅读

（问题代码）

with open("InputFileData.csv") as file:
    SampleTotalHours = file.readlines();

TotalHours = []

for element in SampleTotalHours:
     TotalHours.append(element.strip())

Sum = sum(TotalHours[0])
print(Sum)

(内容“InputFileData.csv”)

40.1,39.7,40,38 
36,36,35.5,35.8
40,41.6,40.3,40
20.4,22.8,20,20

（输出）

Traceback (most recent call last):
    File "D:\Assignment 6 Files\PAtest.py", line 10, in <module>
        Sum = sum(TotalHours[0])
    TypeError: unsupported operand type(s) for +: 'int' and 'str'

Answer 1

有点像这样。对于每一行，以逗号分隔，将字段转换为浮点数，然后对浮点数求和。您可能会发现使用 csv 模块更容易，但使用此数据集并没有真正让您受益。

TotalHours = []
with open("InputFileData.csv") as file:
    for line in file:
        parts = [float(k) for k in line.strip().split(',')]
        TotalHours.append( sum(parts) )
print(TotalHours)

Answer 2

readlines() 将 return 一个字符串列表，在这种情况下第一项是“40.1,39.7,40,38”。要求和，您需要先用分隔符拆分字符串，然后在求和之前将每个值转换为浮点数。

TotalHours = []

for element in SampleTotalHours:
    hoursAsStrings = element.split(',')
    hoursAsFloats = [float(hourString) for hourString in hoursAsStrings]
    TotalHours.append(sum(hoursAsFloats))

TotalHours 是一个列表，其中每个值都是其对应行的总和。

Answer 3

这对我来说很好：

TotalHours = 0

with open("InputFileData.csv") as file:
    for line in file:
        for number in line.strip().split(","):
            if number.replace('.', "").isnumeric():
                TotalHours += float(number)

print(TotalHours)

Answer 4

这里有一些流行的库可供查看（第一个是内置的，另一个是第 3 方）：

import csv

with open('InputFileData.csv', newline='') as file:
    reader = csv.reader(file,quoting=csv.QUOTE_NONNUMERIC)
    for row in reader:
        print(row,sum(row))

输出：

[40.1, 39.7, 40.0, 38.0] 157.8
[36.0, 36.0, 35.5, 35.8] 143.3
[40.0, 41.6, 40.3, 40.0] 161.89999999999998
[20.4, 22.8, 20.0, 20.0] 83.2

import pandas as pd

df = pd.read_csv('InputFileData.csv',header=None)
df['Sum'] = df.sum(axis=1)
print(df)

输出：

      0     1     2     3    Sum
0  40.1  39.7  40.0  38.0  157.8
1  36.0  36.0  35.5  35.8  143.3
2  40.0  41.6  40.3  40.0  161.9
3  20.4  22.8  20.0  20.0   83.2

使用 sum 时如何避免出现不受支持的类型错误

How to aviod getting unsupported type(s) error when using sum

python

csv

sum