pandas.core.groupby.DataFrameGroupBy.agg¶
- DataFrameGroupBy.agg(arg, *args, **kwargs)¶
Aggregate using input function or dict of {column -> function}
Parameters: arg : function or dict
Function to use for aggregating groups. If a function, must either work when passed a DataFrame or when passed to DataFrame.apply. If passed a dict, the keys must be DataFrame column names.
- Accepted Combinations are:
- string cythonized function name
- function
- list of functions
- dict of columns -> functions
- nested dict of names -> dicts of functions
Returns: aggregated : DataFrame
Notes
Numpy functions mean/median/prod/sum/std/var are special cased so the default behavior is applying the function along axis=0 (e.g., np.mean(arr_2d, axis=0)) as opposed to mimicking the default Numpy behavior (e.g., np.mean(arr_2d)).