"""
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Includes test for last_valid_index.
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"""
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import numpy as np
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import pytest
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from pandas import (
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DataFrame,
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Series,
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)
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import pandas._testing as tm
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|
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class TestFirstValidIndex:
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def test_first_valid_index_single_nan(self, frame_or_series):
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# GH#9752 Series/DataFrame should both return None, not raise
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obj = frame_or_series([np.nan])
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assert obj.first_valid_index() is None
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assert obj.iloc[:0].first_valid_index() is None
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@pytest.mark.parametrize(
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"empty", [DataFrame(), Series(dtype=object), Series([], index=[], dtype=object)]
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)
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def test_first_valid_index_empty(self, empty):
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# GH#12800
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assert empty.last_valid_index() is None
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assert empty.first_valid_index() is None
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@pytest.mark.parametrize(
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"data,idx,expected_first,expected_last",
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[
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({"A": [1, 2, 3]}, [1, 1, 2], 1, 2),
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({"A": [1, 2, 3]}, [1, 2, 2], 1, 2),
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({"A": [1, 2, 3, 4]}, ["d", "d", "d", "d"], "d", "d"),
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({"A": [1, np.nan, 3]}, [1, 1, 2], 1, 2),
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({"A": [np.nan, np.nan, 3]}, [1, 1, 2], 2, 2),
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({"A": [1, np.nan, 3]}, [1, 2, 2], 1, 2),
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],
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)
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def test_first_last_valid_frame(self, data, idx, expected_first, expected_last):
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# GH#21441
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df = DataFrame(data, index=idx)
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assert expected_first == df.first_valid_index()
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assert expected_last == df.last_valid_index()
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@pytest.mark.parametrize("index_func", [tm.makeStringIndex, tm.makeDateIndex])
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def test_first_last_valid(self, index_func):
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N = 30
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index = index_func(N)
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mat = np.random.randn(N)
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mat[:5] = np.nan
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mat[-5:] = np.nan
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frame = DataFrame({"foo": mat}, index=index)
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assert frame.first_valid_index() == frame.index[5]
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assert frame.last_valid_index() == frame.index[-6]
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ser = frame["foo"]
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assert ser.first_valid_index() == frame.index[5]
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assert ser.last_valid_index() == frame.index[-6]
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@pytest.mark.parametrize("index_func", [tm.makeStringIndex, tm.makeDateIndex])
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def test_first_last_valid_all_nan(self, index_func):
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# GH#17400: no valid entries
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index = index_func(30)
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frame = DataFrame(np.nan, columns=["foo"], index=index)
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assert frame.last_valid_index() is None
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assert frame.first_valid_index() is None
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ser = frame["foo"]
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assert ser.first_valid_index() is None
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assert ser.last_valid_index() is None
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