The main task of DataFrame.aggregate() function is to apply some aggregation to one or more column. Most frequently used aggregations are:
sum: It is used to return the sum of the values for the requested axis.
min: It is used to return the minimum of the values for the requested axis.
max: It is used to return the maximum values for the requested axis.
func: It refers callable, string, dictionary, or list of string/callables.
It is used for aggregating the data. For a function, it must either work when passed to a DataFrame or DataFrame.apply(). For a DataFrame, it can pass a dict, if the keys are the column names.
axis: (default 0): It refers to 0 or 'index', 1 or 'columns'
0 or 'index': It is an apply function for each column.
1 or 'columns': It is an apply function for each row.
*args: It is a positional argument that is to be passed to func.
**kwargs: It is a keyword argument that is to be passed to the func.
It returns the scalar, Series or DataFrame.
scalar: It is being used when Series.agg is called with the single function.
Series: It is being used when DataFrame.agg is called for the single function.
DataFrame: It is being used when DataFrame.agg is called for the several functions.
X Y Z sum 29.0 38.0 46.0 min 1.0 5.0 7.0
X Y max NaN 21.0 min 1.0 12.0 sum 29.0 NaN