如何使用 pandas.DataFrame.sum() 按 column-indexnumber 而不是 index-string 对列求和

Question

I have the following file where for each column name, there are several columns. So, I cant refer to columns by string. I think I should use an indexnumber. However, I dont know how to do it.

I tried the following code to sum the "D" column ("Banana"):

column_list=[3]
x = file[column_list].sum(axis='rows')
x

But I get an error message stating:

KeyError: "None of [Int64Index([3], dtype='int64')] are in the [columns]"

Answer 1

file.iloc[:,3].sum()

should do the trick. But you would be much better off, keeping your dataframe consistent, ie avoid duplicate column names.