| Current File : //usr/local/lib64/python3.6/site-packages/pandas/tests/io/parser/test_python_parser_only.py |
"""
Tests that apply specifically to the Python parser. Unless specifically
stated as a Python-specific issue, the goal is to eventually move as many of
these tests out of this module as soon as the C parser can accept further
arguments when parsing.
"""
import csv
from io import BytesIO, StringIO
import pytest
from pandas.errors import ParserError
from pandas import DataFrame, Index, MultiIndex
import pandas._testing as tm
def test_default_separator(python_parser_only):
# see gh-17333
#
# csv.Sniffer in Python treats "o" as separator.
data = "aob\n1o2\n3o4"
parser = python_parser_only
expected = DataFrame({"a": [1, 3], "b": [2, 4]})
result = parser.read_csv(StringIO(data), sep=None)
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize("skipfooter", ["foo", 1.5, True])
def test_invalid_skipfooter_non_int(python_parser_only, skipfooter):
# see gh-15925 (comment)
data = "a\n1\n2"
parser = python_parser_only
msg = "skipfooter must be an integer"
with pytest.raises(ValueError, match=msg):
parser.read_csv(StringIO(data), skipfooter=skipfooter)
def test_invalid_skipfooter_negative(python_parser_only):
# see gh-15925 (comment)
data = "a\n1\n2"
parser = python_parser_only
msg = "skipfooter cannot be negative"
with pytest.raises(ValueError, match=msg):
parser.read_csv(StringIO(data), skipfooter=-1)
@pytest.mark.parametrize("kwargs", [dict(sep=None), dict(delimiter="|")])
def test_sniff_delimiter(python_parser_only, kwargs):
data = """index|A|B|C
foo|1|2|3
bar|4|5|6
baz|7|8|9
"""
parser = python_parser_only
result = parser.read_csv(StringIO(data), index_col=0, **kwargs)
expected = DataFrame(
[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
columns=["A", "B", "C"],
index=Index(["foo", "bar", "baz"], name="index"),
)
tm.assert_frame_equal(result, expected)
def test_sniff_delimiter_comment(python_parser_only):
data = """# comment line
index|A|B|C
# comment line
foo|1|2|3 # ignore | this
bar|4|5|6
baz|7|8|9
"""
parser = python_parser_only
result = parser.read_csv(StringIO(data), index_col=0, sep=None, comment="#")
expected = DataFrame(
[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
columns=["A", "B", "C"],
index=Index(["foo", "bar", "baz"], name="index"),
)
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize("encoding", [None, "utf-8"])
def test_sniff_delimiter_encoding(python_parser_only, encoding):
parser = python_parser_only
data = """ignore this
ignore this too
index|A|B|C
foo|1|2|3
bar|4|5|6
baz|7|8|9
"""
if encoding is not None:
from io import TextIOWrapper
data = data.encode(encoding)
data = BytesIO(data)
data = TextIOWrapper(data, encoding=encoding)
else:
data = StringIO(data)
result = parser.read_csv(data, index_col=0, sep=None, skiprows=2, encoding=encoding)
expected = DataFrame(
[[1, 2, 3], [4, 5, 6], [7, 8, 9]],
columns=["A", "B", "C"],
index=Index(["foo", "bar", "baz"], name="index"),
)
tm.assert_frame_equal(result, expected)
def test_single_line(python_parser_only):
# see gh-6607: sniff separator
parser = python_parser_only
result = parser.read_csv(StringIO("1,2"), names=["a", "b"], header=None, sep=None)
expected = DataFrame({"a": [1], "b": [2]})
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize("kwargs", [dict(skipfooter=2), dict(nrows=3)])
def test_skipfooter(python_parser_only, kwargs):
# see gh-6607
data = """A,B,C
1,2,3
4,5,6
7,8,9
want to skip this
also also skip this
"""
parser = python_parser_only
result = parser.read_csv(StringIO(data), **kwargs)
expected = DataFrame([[1, 2, 3], [4, 5, 6], [7, 8, 9]], columns=["A", "B", "C"])
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize(
"compression,klass", [("gzip", "GzipFile"), ("bz2", "BZ2File")]
)
def test_decompression_regex_sep(python_parser_only, csv1, compression, klass):
# see gh-6607
parser = python_parser_only
with open(csv1, "rb") as f:
data = f.read()
data = data.replace(b",", b"::")
expected = parser.read_csv(csv1)
module = pytest.importorskip(compression)
klass = getattr(module, klass)
with tm.ensure_clean() as path:
tmp = klass(path, mode="wb")
tmp.write(data)
tmp.close()
result = parser.read_csv(path, sep="::", compression=compression)
tm.assert_frame_equal(result, expected)
def test_read_csv_buglet_4x_multi_index(python_parser_only):
# see gh-6607
data = """ A B C D E
one two three four
a b 10.0032 5 -0.5109 -2.3358 -0.4645 0.05076 0.3640
a q 20 4 0.4473 1.4152 0.2834 1.00661 0.1744
x q 30 3 -0.6662 -0.5243 -0.3580 0.89145 2.5838"""
parser = python_parser_only
expected = DataFrame(
[
[-0.5109, -2.3358, -0.4645, 0.05076, 0.3640],
[0.4473, 1.4152, 0.2834, 1.00661, 0.1744],
[-0.6662, -0.5243, -0.3580, 0.89145, 2.5838],
],
columns=["A", "B", "C", "D", "E"],
index=MultiIndex.from_tuples(
[("a", "b", 10.0032, 5), ("a", "q", 20, 4), ("x", "q", 30, 3)],
names=["one", "two", "three", "four"],
),
)
result = parser.read_csv(StringIO(data), sep=r"\s+")
tm.assert_frame_equal(result, expected)
def test_read_csv_buglet_4x_multi_index2(python_parser_only):
# see gh-6893
data = " A B C\na b c\n1 3 7 0 3 6\n3 1 4 1 5 9"
parser = python_parser_only
expected = DataFrame.from_records(
[(1, 3, 7, 0, 3, 6), (3, 1, 4, 1, 5, 9)],
columns=list("abcABC"),
index=list("abc"),
)
result = parser.read_csv(StringIO(data), sep=r"\s+")
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize("add_footer", [True, False])
def test_skipfooter_with_decimal(python_parser_only, add_footer):
# see gh-6971
data = "1#2\n3#4"
parser = python_parser_only
expected = DataFrame({"a": [1.2, 3.4]})
if add_footer:
# The stray footer line should not mess with the
# casting of the first two lines if we skip it.
kwargs = dict(skipfooter=1)
data += "\nFooter"
else:
kwargs = dict()
result = parser.read_csv(StringIO(data), names=["a"], decimal="#", **kwargs)
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize(
"sep", ["::", "#####", "!!!", "123", "#1!c5", "%!c!d", "@@#4:2", "_!pd#_"]
)
@pytest.mark.parametrize(
"encoding", ["utf-16", "utf-16-be", "utf-16-le", "utf-32", "cp037"]
)
def test_encoding_non_utf8_multichar_sep(python_parser_only, sep, encoding):
# see gh-3404
expected = DataFrame({"a": [1], "b": [2]})
parser = python_parser_only
data = "1" + sep + "2"
encoded_data = data.encode(encoding)
result = parser.read_csv(
BytesIO(encoded_data), sep=sep, names=["a", "b"], encoding=encoding
)
tm.assert_frame_equal(result, expected)
@pytest.mark.parametrize("quoting", [csv.QUOTE_MINIMAL, csv.QUOTE_NONE])
def test_multi_char_sep_quotes(python_parser_only, quoting):
# see gh-13374
kwargs = dict(sep=",,")
parser = python_parser_only
data = 'a,,b\n1,,a\n2,,"2,,b"'
msg = "ignored when a multi-char delimiter is used"
def fail_read():
with pytest.raises(ParserError, match=msg):
parser.read_csv(StringIO(data), quoting=quoting, **kwargs)
if quoting == csv.QUOTE_NONE:
# We expect no match, so there should be an assertion
# error out of the inner context manager.
with pytest.raises(AssertionError):
fail_read()
else:
fail_read()
def test_none_delimiter(python_parser_only, capsys):
# see gh-13374 and gh-17465
parser = python_parser_only
data = "a,b,c\n0,1,2\n3,4,5,6\n7,8,9"
expected = DataFrame({"a": [0, 7], "b": [1, 8], "c": [2, 9]})
# We expect the third line in the data to be
# skipped because it is malformed, but we do
# not expect any errors to occur.
result = parser.read_csv(
StringIO(data), header=0, sep=None, warn_bad_lines=True, error_bad_lines=False
)
tm.assert_frame_equal(result, expected)
captured = capsys.readouterr()
assert "Skipping line 3" in captured.err
@pytest.mark.parametrize("data", ['a\n1\n"b"a', 'a,b,c\ncat,foo,bar\ndog,foo,"baz'])
@pytest.mark.parametrize("skipfooter", [0, 1])
def test_skipfooter_bad_row(python_parser_only, data, skipfooter):
# see gh-13879 and gh-15910
msg = "parsing errors in the skipped footer rows"
parser = python_parser_only
def fail_read():
with pytest.raises(ParserError, match=msg):
parser.read_csv(StringIO(data), skipfooter=skipfooter)
if skipfooter:
fail_read()
else:
# We expect no match, so there should be an assertion
# error out of the inner context manager.
with pytest.raises(AssertionError):
fail_read()
def test_malformed_skipfooter(python_parser_only):
parser = python_parser_only
data = """ignore
A,B,C
1,2,3 # comment
1,2,3,4,5
2,3,4
footer
"""
msg = "Expected 3 fields in line 4, saw 5"
with pytest.raises(ParserError, match=msg):
parser.read_csv(StringIO(data), header=1, comment="#", skipfooter=1)