dtoolkit.transformer.DropTF#

class dtoolkit.transformer.DropTF(*args, **kwargs)[source]#

A transformer could drop specified labels from rows or columns.

See also

pandas.DataFrame.drop: This transformer’s prototype method.

Notes

drop()’s inplace parameter is not work for this transformer. Actually this break pipeline stream. If a transformer’s inplace is True, the next tf input would get None.

Examples

>>> import numpy as np
>>> import pandas as pd
>>> from dtoolkit.transformer import DropTF
>>> df = pd.DataFrame(np.arange(12).reshape(3, 4),
...                   columns=['A', 'B', 'C', 'D'])
>>> df
    A  B   C   D
0  0  1   2   3
1  4  5   6   7
2  8  9  10  11

Drop columns

>>> tf = DropTF(['B', 'C'], axis=1)
>>> tf.transform(df)
    A   D
0  0   3
1  4   7
2  8  11

Drop a row by index

>>> tf = DropTF([0, 1])
>>> tf.transform(df)
    A  B   C   D
2  8  9  10  11

Drop columns and/or rows of MultiIndex DataFrame

>>> midx = pd.MultiIndex(levels=[['llama', 'cow', 'falcon'],
...                              ['speed', 'weight', 'length']],
...                      codes=[[0, 0, 0, 1, 1, 1, 2, 2, 2],
...                             [0, 1, 2, 0, 1, 2, 0, 1, 2]])
>>> df = pd.DataFrame(index=midx, columns=['big', 'small'],
...                   data=[[45, 30], [200, 100], [1.5, 1], [30, 20],
...                         [250, 150], [1.5, 0.8], [320, 250],
...                         [1, 0.8], [0.3, 0.2]])
>>> df
                big     small
llama    speed   45.0    30.0
        weight  200.0   100.0
        length  1.5     1.0
cow     speed   30.0    20.0
        weight  250.0   150.0
        length  1.5     0.8
falcon  speed   320.0   250.0
        weight  1.0     0.8
        length  0.3     0.2

>>> tf = DropTF(index='cow', columns='small')
>>> tf.transform(df)
llama    speed      45.0
        weight    200.0
        length      1.5
falcon  speed     320.0
        weight      1.0
        length      0.3
Name: big, dtype: float64

>>> tf = DropTF(index='length', level=1)
>>> tf.transform(df)
                big     small
llama    speed   45.0    30.0
        weight  200.0   100.0
cow     speed   30.0    20.0
        weight  250.0   150.0
falcon  speed   320.0   250.0
        weight  1.0     0.8

Attributes:

inverse_transform_method

Methods

`fit`(*_)	Fit transformer.
`fit_transform`(X[, y])	Fit to data, then transform it.
`inverse_transform`(X)	Undo transform to `X`.
`set_output`(*[, transform])	Set output container.
`transform`(X)	Transform `X`.
`transform_method`(self[, labels, axis, ...])	Drop specified labels from rows or columns.
`update_invargs`(args, *kwargs)	Inverse transform method argument entry.