Python Pandas Inner加入2个具有不同标题的csv文件

Question

I did some research but cant find the answer for my case I have 2 csv files

a.csv

id, fname, lname, address
1, aaa, bbb, ccc
2, abb, ccb, ddd
3, ddd, eee, fff
4, eee, ggg, fff
5, EEE, GGG, RRRR

and 2nd file

b.csv

ID
1
3
5

desire result would be (the id header below is not strict but id would be fine)

id, fname, lname, address
1, aaa, bbb, ccc
3, ddd, eee, fff
5, EEE, GGG, RRRR

what i tried

merged = a.merge(b, left_on = ['id'],
                right_on= ['ID'],
                how = 'inner')
merged.to_csv(r'C:\things\output.csv', index=False)

and got a cannot allocate memory for array error...

edit:

the code below would work fine if headers are exactly the same (both are 'id')but life is not perfect

merged = a.merge(b, on = 'id')

Answer 1

使用isin 。

merged=a.loc[a.id.isin(b.ID),:]

Answer 2

I think you should just be able to do

merged = pd.merge(a, b, left_on = ['id'],
            right_on= ['ID'],
            how = 'inner').drop('ID', axis='columns')
merged.to_csv(r'C:\things\output.csv', index=False)