CODEWITHSUNDEEP
pythonpandasdataframegroup-bymerge
nbrown049
nbrown049

Reputation: 1

Python pandas Groupby() function

I'm looking to use values from a dataframe generated through Groupby(). The command I wrote was:

pitcher_avg = total_data.groupby(['PitcherID','PitchType'])['ReleaseSpeed'].mean()

The pitcher_avg output was:

PitcherID  PitchType
80027      CF           86.022476
           CH           80.846935
           FB           89.614138
           SI           86.953833
           SL           80.533818

My next step is taking the values in the right-hand column, and merging them into a new dataframe on the condition that the PitcherID matched the PitcherID in the new dataframe. For example:

           GameDate  PitcherID    ...            CF            CH
0        2018-03-29      80027    ...     86.022476     80.846935
1        2018-03-29      80027    ...     86.022476     80.846935
2        2018-03-29      80027    ...     86.022476     80.846935
3        2018-03-29      80027    ...     86.022476     80.846935
4        2018-03-29      80027    ...     86.022476     80.846935

Is this possible? I've been trying np.where and pd.merge commands, but nothing has worked yet. Thank you!

Upvotes: 0

Views: 68

Answers (1)

euh
euh

Reputation: 451

I think you should do .reset_index() and rename new column after the groupy by. Merge should work after that. You can specify in merge on which columns to merge i.e. df_original.merge(grouped_results_df, how ='left', indicator =True, on = ['PitcherID','PitcherType','NewColumn'])

Upvotes: 1

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