python - 如何将值解析为带有列名的csv

Question

我想更新 csv 文件中的特定列。我想更新函数 func1 中的第一列和函数 func2 中的第二列:

def func1(x):
    data = 'test1'
    file = open("test.csv","a+")
    file.write(data)
    file.close()
    return data

def func2(x):
    data = 'test2'
    file = open("test.csv","a+")
    file.write(data)
    file.close()
    return data

预期结果

col1,col2
test1,test2

如何指定要更新的列？此处，没有创建任何文件。

Answer 1

您可以使用pandas包来更新特定列(如果您没有它，您可以通过在终端中运行pip install pandas来安装它):

import pandas as pd

def func1(file):        
    column = 'col1'
    data = 'new_test1'
    file[column] = data
    return data
def func2(file):  
    column = 'col2'      
    data = 'new_test2'
    file[column] = data
    return data

# you should open the file only once, you don't need to open it seperately within each function
df = pd.read_csv('data.csv')

print(df)
#    col1   col2
# 0  test1  test2
# the '0' is an index column, you can remove it when writing to the file (using index=False, see below)

data1 = func1 (df)
data2 = func2 (df)

df.to_csv('data.csv', index=False) # with 'index=False' you won't see an index column in data.csv

print(df)
#        col1       col2
# 0  new_test1  new_test2

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