Looking for lookup code to add columns to Pandas dataframe queried from same dataframe

Question

I am trying to add columns to a dataframe based on another row of the same dataframe. I would like to look up the row with the first column value equal to the value in column 5 and append columns 2, 3, and 4 to the dataframe as below

1  2  3  4  5
a  b  c  d  i
e  f  g  h  i
i  j  k  l  e

1  2  3  4  5  2a 3a 4a
a  b  c  d  i  j  k  l
e  f  g  h  i  j  k  l
i  j  k  l  e  f  g  h

I have tried creating another table to merge df2 = df.loc[(df.1 == df.5) in various combinations but no luck.

Do any of the links here help? stackoverflow.com/questions/64182958/… — Arthur Morris
– Arthur Morris, Commented Oct 21, 2020 at 6:58
Thanks for the suggestion. That was a good place to start. In the process I realized though that i could just merge it with itself — Carl Clifford
– Carl Clifford, Commented Oct 27, 2020 at 3:11

Arthur Morris · Accepted Answer · 2020-10-27 06:35:55Z

0

Decided to merge the dataframe with itself:

dfleft = df.merge(df,how='left', left_on='5', right_on='1')

just need to rename columns after that

edited Oct 27, 2020 at 6:35

Arthur Morris

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answered Oct 27, 2020 at 3:15

Carl Clifford

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