add new column based on mutual value in 2 dataframes

Question

I have 2 dataframes:

df1:

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and df2:

enter image description here

They have differnet size. The common parts between these dataframes is the columns B (df1) and Z (df2), and based on columns B and Z I want to obtain new dataframe:

enter image description here

That add the major of student that are common between df1 and df2 and if it doesn't exist in df2 have empty value.

Please add your data frame in code for for better assistance. — ArchAngelPwn, May 10 '22 at 18:11
Does this answer your question? [Pandas Merging 101](https://stackoverflow.com/questions/53645882/pandas-merging-101) — mkrieger1, May 11 '22 at 08:50

Daniele Cappuccio · Answer 1 · 2022-05-11T13:03:20.943

1

You can merge the two dataframes on the B and Z columns, e.g.:

df = pd.merge(left=df1, right=df2, left_on='B', right_on='Z', how='left')

edited May 11 '22 at 13:03

answered May 10 '22 at 18:14

Daniele Cappuccio

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I think you need `how='left'`, otherwise B=85 and B=12 will be missing in the result, won't they? – mkrieger1 May 11 '22 at 08:55

add new column based on mutual value in 2 dataframes

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