52 lines
1.5 KiB
Python
52 lines
1.5 KiB
Python
from io import StringIO
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import numpy as np
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import pytest
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from pandas import DataFrame, concat, read_csv
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import pandas._testing as tm
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class TestInvalidConcat:
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def test_concat_invalid(self):
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# trying to concat a ndframe with a non-ndframe
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df1 = tm.makeCustomDataframe(10, 2)
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for obj in [1, {}, [1, 2], (1, 2)]:
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msg = (
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f"cannot concatenate object of type '{type(obj)}'; "
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"only Series and DataFrame objs are valid"
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)
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with pytest.raises(TypeError, match=msg):
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concat([df1, obj])
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def test_concat_invalid_first_argument(self):
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df1 = tm.makeCustomDataframe(10, 2)
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df2 = tm.makeCustomDataframe(10, 2)
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msg = (
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"first argument must be an iterable of pandas "
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'objects, you passed an object of type "DataFrame"'
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)
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with pytest.raises(TypeError, match=msg):
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concat(df1, df2)
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# generator ok though
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concat(DataFrame(np.random.rand(5, 5)) for _ in range(3))
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# text reader ok
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# GH6583
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data = """index,A,B,C,D
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foo,2,3,4,5
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bar,7,8,9,10
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baz,12,13,14,15
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qux,12,13,14,15
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foo2,12,13,14,15
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bar2,12,13,14,15
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"""
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with read_csv(StringIO(data), chunksize=1) as reader:
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result = concat(reader, ignore_index=True)
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expected = read_csv(StringIO(data))
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tm.assert_frame_equal(result, expected)
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