test_factorize.py

import numpy as np

from pandas import PeriodIndex
import pandas._testing as tm


class TestFactorize:
    def test_factorize(self):
        idx1 = PeriodIndex(
            ["2014-01", "2014-01", "2014-02", "2014-02", "2014-03", "2014-03"], freq="M"
        )

        exp_arr = np.array([0, 0, 1, 1, 2, 2], dtype=np.intp)
        exp_idx = PeriodIndex(["2014-01", "2014-02", "2014-03"], freq="M")

        arr, idx = idx1.factorize()
        tm.assert_numpy_array_equal(arr, exp_arr)
        tm.assert_index_equal(idx, exp_idx)

        arr, idx = idx1.factorize(sort=True)
        tm.assert_numpy_array_equal(arr, exp_arr)
        tm.assert_index_equal(idx, exp_idx)

        idx2 = PeriodIndex(
            ["2014-03", "2014-03", "2014-02", "2014-01", "2014-03", "2014-01"], freq="M"
        )

        exp_arr = np.array([2, 2, 1, 0, 2, 0], dtype=np.intp)
        arr, idx = idx2.factorize(sort=True)
        tm.assert_numpy_array_equal(arr, exp_arr)
        tm.assert_index_equal(idx, exp_idx)

        exp_arr = np.array([0, 0, 1, 2, 0, 2], dtype=np.intp)
        exp_idx = PeriodIndex(["2014-03", "2014-02", "2014-01"], freq="M")
        arr, idx = idx2.factorize()
        tm.assert_numpy_array_equal(arr, exp_arr)
        tm.assert_index_equal(idx, exp_idx)