Python : How to bring value from one dataframe to another dataframe?

Question

df1 = pd.DataFrame({'user': ['Bob','Bob','Bob'],'income':[400,500, 420],'expenses':[400,2500,420]})
df1.user.unique()

return_val = df[(df['Payer']=='Bob')]

I have two dataframes (df and df1) and I do not want to hard code 'Bob' in return_val. Is there anyway through which I can get 'Bob' by reading df1 ? Am trying something like this which seems incomplete.

return_val = df[(df['Payer']== df1.user.unique())]

What exactly are you trying to do? There's no `mapping` in your question. — Quang Hoang, Feb 13 '20 at 18:20
I edited my question. In 'return_val' I want to bring 'Bob' from df1 without hard coding df['Payer']=='Bob'. 'Bob' should read from df1. — Akash, Feb 13 '20 at 18:24
`return_val = df[(df['Payer']==df1.user.unique()[0])]` or `return_val = df[(df['Payer']==df1['user'].iat[0])]` , however the question is unclear as mentioned — anky, Feb 13 '20 at 18:27
use `df.loc[df['Payer'].isin(df1['user'])]` or ...`df.merge(df1[['user']],left_on = 'Payer', right_on ='user', how ='right').loc[:,df.columns]` — ansev, Feb 13 '20 at 18:30
@anky_91I was missing [0] in unique() and thats why giving unusual results. Thanks for everything. — Akash, Feb 13 '20 at 20:50

Mohammed Khalid · Answer 1 · 2020-02-13T21:47:04.477

0

mask=df1['user'].unique()[0]
return_val = df[mask]

but it work only if you have 'Bob' only in the 'user' column

edited Feb 13 '20 at 21:47

answered Feb 13 '20 at 18:27

Mohammed Khalid

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Yes. there is only 'Bob' in the column. There are multiple files having different user names. – Akash Feb 13 '20 at 20:49

Python : How to bring value from one dataframe to another dataframe?

1 Answers1