Pandas groupby(),agg() – how to return results without the multi index?

Below call: >>> gr = df.groupby([‘EVENT_ID’, ‘SELECTION_ID’], as_index=False) >>> res = gr.agg({‘ODDS’:[np.min, np.max]}) >>> res EVENT_ID SELECTION_ID ODDS amin amax 0 100429300 5297529 18 25 1 100429300 5297559 30 38 returns a frame with mulit-index columns. If you do not want columns to be multi-index either you may do: >>> res.columns = list(map(”.join, res.columns.values)) >>> … Read more

Why can’t indexed views have a MAX() aggregate?

These aggregates are not allowed because they cannot be recomputed solely based on the changed values. Some aggregates, like COUNT_BIG() or SUM(), can be recomputed just by looking at the data that changed. These are allowed within an indexed view because, if an underlying value changes, the impact of that change can be directly calculated. … Read more

Explain the aggregate functionality in Spark (with Python and Scala)

I wasn’t fully convinced from the accepted answer, and JohnKnight’s answer helped, so here’s my point of view: First, let’s explain aggregate() in my own words: Prototype: aggregate(zeroValue, seqOp, combOp) Description: aggregate() lets you take an RDD and generate a single value that is of a different type than what was stored in the original … Read more

Solution for SpecificationError: nested renamer is not supported while agg() along with groupby()

change temp[‘total’] = pd.DataFrame(project_data.groupby(col1)[col2].agg({‘total’:’count’})).reset_index()[‘total’] temp[‘Avg’] = pd.DataFrame(project_data.groupby(col1)[col2].agg({‘Avg’:’mean’})).reset_index()[‘Avg’] to temp[‘total’] = pd.DataFrame(project_data.groupby(col1)[col2].agg(total=”count”)).reset_index()[‘total’] temp[‘Avg’] = pd.DataFrame(project_data.groupby(col1)[col2].agg(Avg=’mean’)).reset_index()[‘Avg’] reason: in new pandas version named aggregation is the recommended replacement for the deprecated “dict-of-dicts” approach to naming the output of column-specific aggregations (Deprecate groupby.agg() with a dictionary when renaming). source: https://pandas.pydata.org/pandas-docs/stable/whatsnew/v0.25.0.html