69 lines
2.2 KiB
Python
69 lines
2.2 KiB
Python
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"""
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test_insert is specifically for the DataFrame.insert method; not to be
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confused with tests with "insert" in their names that are really testing
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__setitem__.
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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 DataFrame, Index
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import pandas._testing as tm
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class TestDataFrameInsert:
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def test_insert(self):
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df = DataFrame(
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np.random.randn(5, 3), index=np.arange(5), columns=["c", "b", "a"]
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)
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df.insert(0, "foo", df["a"])
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tm.assert_index_equal(df.columns, Index(["foo", "c", "b", "a"]))
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tm.assert_series_equal(df["a"], df["foo"], check_names=False)
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df.insert(2, "bar", df["c"])
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tm.assert_index_equal(df.columns, Index(["foo", "c", "bar", "b", "a"]))
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tm.assert_almost_equal(df["c"], df["bar"], check_names=False)
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with pytest.raises(ValueError, match="already exists"):
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df.insert(1, "a", df["b"])
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msg = "cannot insert c, already exists"
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with pytest.raises(ValueError, match=msg):
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df.insert(1, "c", df["b"])
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df.columns.name = "some_name"
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# preserve columns name field
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df.insert(0, "baz", df["c"])
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assert df.columns.name == "some_name"
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def test_insert_column_bug_4032(self):
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# GH#4032, inserting a column and renaming causing errors
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df = DataFrame({"b": [1.1, 2.2]})
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df = df.rename(columns={})
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df.insert(0, "a", [1, 2])
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result = df.rename(columns={})
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str(result)
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expected = DataFrame([[1, 1.1], [2, 2.2]], columns=["a", "b"])
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tm.assert_frame_equal(result, expected)
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df.insert(0, "c", [1.3, 2.3])
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result = df.rename(columns={})
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str(result)
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expected = DataFrame([[1.3, 1, 1.1], [2.3, 2, 2.2]], columns=["c", "a", "b"])
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tm.assert_frame_equal(result, expected)
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def test_insert_with_columns_dups(self):
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# GH#14291
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df = DataFrame()
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df.insert(0, "A", ["g", "h", "i"], allow_duplicates=True)
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df.insert(0, "A", ["d", "e", "f"], allow_duplicates=True)
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df.insert(0, "A", ["a", "b", "c"], allow_duplicates=True)
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exp = DataFrame(
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[["a", "d", "g"], ["b", "e", "h"], ["c", "f", "i"]], columns=["A", "A", "A"]
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)
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tm.assert_frame_equal(df, exp)
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