111 lines
3.7 KiB
Python
111 lines
3.7 KiB
Python
"""
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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.errors import PerformanceWarning
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from pandas import (
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DataFrame,
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Index,
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)
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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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def test_insert_item_cache(self, using_array_manager, using_copy_on_write):
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df = DataFrame(np.random.randn(4, 3))
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ser = df[0]
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if using_array_manager:
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expected_warning = None
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else:
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# with BlockManager warn about high fragmentation of single dtype
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expected_warning = PerformanceWarning
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with tm.assert_produces_warning(expected_warning):
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for n in range(100):
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df[n + 3] = df[1] * n
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if using_copy_on_write:
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ser.iloc[0] = 99
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assert df.iloc[0, 0] == df[0][0]
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assert df.iloc[0, 0] != 99
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else:
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ser.values[0] = 99
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assert df.iloc[0, 0] == df[0][0]
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assert df.iloc[0, 0] == 99
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def test_insert_EA_no_warning(self):
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# PerformanceWarning about fragmented frame should not be raised when
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# using EAs (https://github.com/pandas-dev/pandas/issues/44098)
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df = DataFrame(np.random.randint(0, 100, size=(3, 100)), dtype="Int64")
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with tm.assert_produces_warning(None):
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df["a"] = np.array([1, 2, 3])
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def test_insert_frame(self):
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# GH#42403
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df = DataFrame({"col1": [1, 2], "col2": [3, 4]})
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msg = r"Expected a 1D array, got an array with shape \(2, 2\)"
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with pytest.raises(ValueError, match=msg):
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df.insert(1, "newcol", df)
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