如何避免在使用sum时出现不支持的类型错误

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，然后获得每行的总和。我尝试剥离列表中的任何东西，但int型和浮点数，并确保文件只有数字。如果有人能帮助我，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 FilesPAtest.py", line 10, in <module>
Sum = sum(TotalHours[0])
TypeError: unsupported operand type(s) for +: 'int' and 'str'

Answer 1

readlines()将返回一个字符串列表，在这种情况下，第一项是"40.1,39.7,40,38"。要得到和，首先需要用分隔符分隔字符串，并在取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，其中每个值是其对应行的和。

Answer 2

就像这样。对于每一行，用逗号分隔，将字段转换为浮点数，将浮点数相加。您可能会发现使用csv模块更容易，但它并没有真正为您提供这个数据集。

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 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参考(一个是内置的，另一个是第三方的):

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