Merge 2 dataframes make sure index is there for left dataframe

Question

I have two dataframes: df_transactions & df_custdemo

I want to merge the two on df_transactions. (i.e. all the customer demographics data should merge onto the transactions data). The merge is done on customer_id, however the index for df_transactions = transaction_id.

When I merge, the final table result does not have the transaction_id column. How can i merge to also get that?

I have tried:

df_custdemo_transactions = df_transactions.merge(df_custdemo, how='left', left_on='customer_id', right_on='customer_id', left_index=True)

and

df_custdemo_transactions = df_transactions.merge(df_custdemo, how='left', left_on='customer_id', right_on='customer_id')

But final result does not have the transaction_id yet.

Have you tried df_custdemo_transactions.reset_index(inplace=True)? — Suneha K S, Aug 25 '20 at 06:26

score 0 · Accepted Answer · answered Aug 25 '20 at 07:18

0

Add the following line before the executing the merge statement.

 df_transactions.reset_index(inplace=True)

answered Aug 25 '20 at 07:18

Mayesh Mohapatra

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Thank you! - how can rename the index to be transaction_id? – Sana Shah Aug 25 '20 at 08:22
You can check this link ( https://stackoverflow.com/questions/19851005/rename-pandas-dataframe-index) on how to rename indexes. – Mayesh Mohapatra Aug 25 '20 at 09:59
Or to be more specific to ur question. After the merge, add this line `df_transactions.set_index('transaction_id',inplace = True)` – Mayesh Mohapatra Aug 25 '20 at 10:04

Merge 2 dataframes make sure index is there for left dataframe

1 Answers1