How to get equivalent of pandas.DataFrame.pivot_table

How to get equivalent of pandas.DataFrame.pivot_table like here

table = pivot_table(df, values=['D', 'E'], index=['A', 'C'], aggfunc={'D': np.mean, 'E': [min, max, np.mean]})

Output:

                  D   E
               mean max median min
A   C
bar large  5.500000  16   14.5  13
    small  5.500000  15   14.5  14
foo large  2.000000  10    9.5   9
    small  2.333333  12   11.0   8

[ashleydavis]

Hi, just to let you know I’ve upgraded the Data-Forge pivot function to support multiple outputs so that you can use it more like Pandas.

So now with Data-Forge 1.0.9 you can do your pivot like this:

const df2 = df1.pivot(["A", "C"], { 
    D: values => values.average(), 
    E: {
        min: values => values.min(),
        max: values => values.max(),
        mean: values => values.average()
    }
});

For an example please see the unit test pivot can produce multiple output values in the pivot tests file.

You also asked for multi-level indexes and columns (like Pandas), but at the moment I’m not planning on implementing this feature for Data-Forge. I’m afraid it’s going to stay in the too-hard basket for the forseeable future.

[ashleydavis]

Great!

You might also be interested know that I’m writing a book on this type of thing.

Please take a look: http://bit.ly/2t2cJu2