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# derived from copyright 1999-2021 Alibaba Group Holding Ltd.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
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import numpy as np
import pandas as pd
from pandas.api.types import is_integer
from ...core import ENTITY_TYPE
from ...tensor import tensor as astensor
from ...tensor.statistics.percentile import percentile
from ..core import DATAFRAME_TYPE, SERIES_TYPE
from ..initializer import DataFrame, Series
from .cut import cut
[docs]def qcut(x, q, labels=None, retbins=False, precision=3, duplicate="raise"):
"""
Quantile-based discretization function.
Discretize variable into equal-sized buckets based on rank or based
on sample quantiles. For example 1000 values for 10 quantiles would
produce a Categorical object indicating quantile membership for each data point.
Parameters
----------
x : 1d tensor or Series
q : int or list-like of float
Number of quantiles. 10 for deciles, 4 for quartiles, etc. Alternately
array of quantiles, e.g. [0, .25, .5, .75, 1.] for quartiles.
labels : array or False, default None
Used as labels for the resulting bins. Must be of the same length as
the resulting bins. If False, return only integer indicators of the
bins. If True, raises an error.
retbins : bool, optional
Whether to return the (bins, labels) or not. Can be useful if bins
is given as a scalar.
precision : int, optional
The precision at which to store and display the bins labels.
duplicates : {default 'raise', 'drop'}, optional
If bin edges are not unique, raise ValueError or drop non-uniques.
Returns
-------
out : Categorical or Series or tensor of integers if labels is False
The return type (Categorical or Series) depends on the input: a Series
of type category if input is a Series else Categorical. Bins are
represented as categories when categorical data is returned.
bins : tensor of floats
Returned only if `retbins` is True.
Notes
-----
Out of bounds values will be NA in the resulting Categorical object
Examples
--------
>>> import mars.dataframe as md
>>> md.qcut(range(5), 4).execute()
... # doctest: +ELLIPSIS
[(-0.001, 1.0], (-0.001, 1.0], (1.0, 2.0], (2.0, 3.0], (3.0, 4.0]]
Categories (4, interval[float64]): [(-0.001, 1.0] < (1.0, 2.0] ...
>>> md.qcut(range(5), 3, labels=["good", "medium", "bad"]).execute()
... # doctest: +SKIP
[good, good, medium, bad, bad]
Categories (3, object): [good < medium < bad]
>>> md.qcut(range(5), 4, labels=False).execute()
array([0, 0, 1, 2, 3])
"""
if is_integer(q):
q = np.linspace(0, 1, q + 1)
if isinstance(x, (DATAFRAME_TYPE, SERIES_TYPE, pd.DataFrame, pd.Series)):
x = DataFrame(x) if x.ndim == 2 else Series(x)
bins = x.quantile(q)
else:
x = astensor(x)
if isinstance(q, ENTITY_TYPE):
q = q * 100
else:
q = [iq * 100 for iq in q]
bins = percentile(x, q)
return cut(
x,
bins,
labels=labels,
retbins=retbins,
precision=precision,
include_lowest=True,
duplicates=duplicate,
)