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