344 lines
10 KiB
Python
344 lines
10 KiB
Python
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"""
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Tests the TextReader class in parsers.pyx, which
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is integral to the C engine in parsers.py
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"""
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from io import (
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BytesIO,
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StringIO,
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)
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import numpy as np
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import pytest
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import pandas._libs.parsers as parser
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from pandas._libs.parsers import TextReader
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from pandas import DataFrame
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import pandas._testing as tm
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from pandas.io.parsers import (
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TextFileReader,
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read_csv,
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)
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from pandas.io.parsers.c_parser_wrapper import ensure_dtype_objs
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class TestTextReader:
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@pytest.fixture
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def csv_path(self, datapath):
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return datapath("io", "data", "csv", "test1.csv")
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def test_file_handle(self, csv_path):
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with open(csv_path, "rb") as f:
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reader = TextReader(f)
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reader.read()
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def test_file_handle_mmap(self, csv_path):
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# this was never using memory_map=True
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with open(csv_path, "rb") as f:
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reader = TextReader(f, header=None)
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reader.read()
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def test_StringIO(self, csv_path):
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with open(csv_path, "rb") as f:
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text = f.read()
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src = BytesIO(text)
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reader = TextReader(src, header=None)
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reader.read()
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def test_string_factorize(self):
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# should this be optional?
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data = "a\nb\na\nb\na"
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reader = TextReader(StringIO(data), header=None)
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result = reader.read()
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assert len(set(map(id, result[0]))) == 2
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def test_skipinitialspace(self):
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data = "a, b\na, b\na, b\na, b"
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reader = TextReader(StringIO(data), skipinitialspace=True, header=None)
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result = reader.read()
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tm.assert_numpy_array_equal(
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result[0], np.array(["a", "a", "a", "a"], dtype=np.object_)
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)
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tm.assert_numpy_array_equal(
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result[1], np.array(["b", "b", "b", "b"], dtype=np.object_)
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)
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def test_parse_booleans(self):
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data = "True\nFalse\nTrue\nTrue"
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reader = TextReader(StringIO(data), header=None)
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result = reader.read()
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assert result[0].dtype == np.bool_
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def test_delimit_whitespace(self):
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data = 'a b\na\t\t "b"\n"a"\t \t b'
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reader = TextReader(StringIO(data), delim_whitespace=True, header=None)
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result = reader.read()
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tm.assert_numpy_array_equal(
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result[0], np.array(["a", "a", "a"], dtype=np.object_)
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)
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tm.assert_numpy_array_equal(
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result[1], np.array(["b", "b", "b"], dtype=np.object_)
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)
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def test_embedded_newline(self):
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data = 'a\n"hello\nthere"\nthis'
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reader = TextReader(StringIO(data), header=None)
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result = reader.read()
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expected = np.array(["a", "hello\nthere", "this"], dtype=np.object_)
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tm.assert_numpy_array_equal(result[0], expected)
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def test_euro_decimal(self):
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data = "12345,67\n345,678"
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reader = TextReader(StringIO(data), delimiter=":", decimal=",", header=None)
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result = reader.read()
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expected = np.array([12345.67, 345.678])
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tm.assert_almost_equal(result[0], expected)
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def test_integer_thousands(self):
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data = "123,456\n12,500"
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reader = TextReader(StringIO(data), delimiter=":", thousands=",", header=None)
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result = reader.read()
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expected = np.array([123456, 12500], dtype=np.int64)
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tm.assert_almost_equal(result[0], expected)
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def test_integer_thousands_alt(self):
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data = "123.456\n12.500"
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reader = TextFileReader(
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StringIO(data), delimiter=":", thousands=".", header=None
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)
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result = reader.read()
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expected = DataFrame([123456, 12500])
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tm.assert_frame_equal(result, expected)
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def test_skip_bad_lines(self, capsys):
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# too many lines, see #2430 for why
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data = "a:b:c\nd:e:f\ng:h:i\nj:k:l:m\nl:m:n\no:p:q:r"
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reader = TextReader(StringIO(data), delimiter=":", header=None)
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msg = r"Error tokenizing data\. C error: Expected 3 fields in line 4, saw 4"
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with pytest.raises(parser.ParserError, match=msg):
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reader.read()
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reader = TextReader(
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StringIO(data), delimiter=":", header=None, on_bad_lines=2 # Skip
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)
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result = reader.read()
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expected = {
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0: np.array(["a", "d", "g", "l"], dtype=object),
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1: np.array(["b", "e", "h", "m"], dtype=object),
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2: np.array(["c", "f", "i", "n"], dtype=object),
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}
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assert_array_dicts_equal(result, expected)
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reader = TextReader(
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StringIO(data), delimiter=":", header=None, on_bad_lines=1 # Warn
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)
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reader.read()
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captured = capsys.readouterr()
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assert "Skipping line 4" in captured.err
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assert "Skipping line 6" in captured.err
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def test_header_not_enough_lines(self):
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data = "skip this\nskip this\na,b,c\n1,2,3\n4,5,6"
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reader = TextReader(StringIO(data), delimiter=",", header=2)
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header = reader.header
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expected = [["a", "b", "c"]]
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assert header == expected
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recs = reader.read()
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expected = {
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0: np.array([1, 4], dtype=np.int64),
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1: np.array([2, 5], dtype=np.int64),
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2: np.array([3, 6], dtype=np.int64),
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}
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assert_array_dicts_equal(recs, expected)
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def test_escapechar(self):
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data = '\\"hello world"\n\\"hello world"\n\\"hello world"'
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reader = TextReader(StringIO(data), delimiter=",", header=None, escapechar="\\")
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result = reader.read()
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expected = {0: np.array(['"hello world"'] * 3, dtype=object)}
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assert_array_dicts_equal(result, expected)
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def test_eof_has_eol(self):
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# handling of new line at EOF
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pass
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def test_na_substitution(self):
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pass
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def test_numpy_string_dtype(self):
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data = """\
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a,1
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aa,2
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aaa,3
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aaaa,4
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aaaaa,5"""
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def _make_reader(**kwds):
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if "dtype" in kwds:
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kwds["dtype"] = ensure_dtype_objs(kwds["dtype"])
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return TextReader(StringIO(data), delimiter=",", header=None, **kwds)
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reader = _make_reader(dtype="S5,i4")
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result = reader.read()
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assert result[0].dtype == "S5"
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ex_values = np.array(["a", "aa", "aaa", "aaaa", "aaaaa"], dtype="S5")
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assert (result[0] == ex_values).all()
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assert result[1].dtype == "i4"
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reader = _make_reader(dtype="S4")
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result = reader.read()
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assert result[0].dtype == "S4"
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ex_values = np.array(["a", "aa", "aaa", "aaaa", "aaaa"], dtype="S4")
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assert (result[0] == ex_values).all()
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assert result[1].dtype == "S4"
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def test_pass_dtype(self):
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data = """\
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one,two
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1,a
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2,b
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3,c
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4,d"""
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def _make_reader(**kwds):
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if "dtype" in kwds:
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kwds["dtype"] = ensure_dtype_objs(kwds["dtype"])
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return TextReader(StringIO(data), delimiter=",", **kwds)
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reader = _make_reader(dtype={"one": "u1", 1: "S1"})
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result = reader.read()
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assert result[0].dtype == "u1"
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assert result[1].dtype == "S1"
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reader = _make_reader(dtype={"one": np.uint8, 1: object})
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result = reader.read()
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assert result[0].dtype == "u1"
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assert result[1].dtype == "O"
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reader = _make_reader(dtype={"one": np.dtype("u1"), 1: np.dtype("O")})
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result = reader.read()
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assert result[0].dtype == "u1"
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assert result[1].dtype == "O"
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def test_usecols(self):
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data = """\
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a,b,c
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1,2,3
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4,5,6
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7,8,9
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10,11,12"""
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def _make_reader(**kwds):
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return TextReader(StringIO(data), delimiter=",", **kwds)
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reader = _make_reader(usecols=(1, 2))
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result = reader.read()
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exp = _make_reader().read()
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assert len(result) == 2
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assert (result[1] == exp[1]).all()
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assert (result[2] == exp[2]).all()
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@pytest.mark.parametrize(
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"text, kwargs",
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[
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("a,b,c\r1,2,3\r4,5,6\r7,8,9\r10,11,12", {"delimiter": ","}),
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(
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"a b c\r1 2 3\r4 5 6\r7 8 9\r10 11 12",
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{"delim_whitespace": True},
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),
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("a,b,c\r1,2,3\r4,5,6\r,88,9\r10,11,12", {"delimiter": ","}),
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(
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(
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"A,B,C,D,E,F,G,H,I,J,K,L,M,N,O\r"
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"AAAAA,BBBBB,0,0,0,0,0,0,0,0,0,0,0,0,0\r"
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",BBBBB,0,0,0,0,0,0,0,0,0,0,0,0,0"
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),
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{"delimiter": ","},
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),
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("A B C\r 2 3\r4 5 6", {"delim_whitespace": True}),
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("A B C\r2 3\r4 5 6", {"delim_whitespace": True}),
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],
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)
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def test_cr_delimited(self, text, kwargs):
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nice_text = text.replace("\r", "\r\n")
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result = TextReader(StringIO(text), **kwargs).read()
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expected = TextReader(StringIO(nice_text), **kwargs).read()
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assert_array_dicts_equal(result, expected)
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def test_empty_field_eof(self):
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data = "a,b,c\n1,2,3\n4,,"
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result = TextReader(StringIO(data), delimiter=",").read()
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expected = {
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0: np.array([1, 4], dtype=np.int64),
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1: np.array(["2", ""], dtype=object),
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2: np.array(["3", ""], dtype=object),
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}
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assert_array_dicts_equal(result, expected)
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# GH5664
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a = DataFrame([["b"], [np.nan]], columns=["a"], index=["a", "c"])
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b = DataFrame([[1, 1, 1, 0], [1, 1, 1, 0]], columns=list("abcd"), index=[1, 1])
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c = DataFrame(
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[
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[1, 2, 3, 4],
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[6, np.nan, np.nan, np.nan],
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[8, 9, 10, 11],
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[13, 14, np.nan, np.nan],
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],
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columns=list("abcd"),
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index=[0, 5, 7, 12],
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)
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for _ in range(100):
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df = read_csv(StringIO("a,b\nc\n"), skiprows=0, names=["a"], engine="c")
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tm.assert_frame_equal(df, a)
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df = read_csv(
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StringIO("1,1,1,1,0\n" * 2 + "\n" * 2), names=list("abcd"), engine="c"
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)
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tm.assert_frame_equal(df, b)
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df = read_csv(
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StringIO("0,1,2,3,4\n5,6\n7,8,9,10,11\n12,13,14"),
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names=list("abcd"),
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engine="c",
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)
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tm.assert_frame_equal(df, c)
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def test_empty_csv_input(self):
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# GH14867
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with read_csv(
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StringIO(), chunksize=20, header=None, names=["a", "b", "c"]
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) as df:
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assert isinstance(df, TextFileReader)
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def assert_array_dicts_equal(left, right):
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for k, v in left.items():
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tm.assert_numpy_array_equal(np.asarray(v), np.asarray(right[k]))
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