Alle Dateien aus dem Pythonkurs
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import numpy as np
import pytest
import pandas as pd
from pandas.core.interchange.utils import dtype_to_arrow_c_fmt
# TODO: use ArrowSchema to get reference C-string.
# At the time, there is no way to access ArrowSchema holding a type format string
# from python. The only way to access it is to export the structure to a C-pointer,
# see DataType._export_to_c() method defined in
# https://github.com/apache/arrow/blob/master/python/pyarrow/types.pxi
@pytest.mark.parametrize(
"pandas_dtype, c_string",
[
(np.dtype("bool"), "b"),
(np.dtype("int8"), "c"),
(np.dtype("uint8"), "C"),
(np.dtype("int16"), "s"),
(np.dtype("uint16"), "S"),
(np.dtype("int32"), "i"),
(np.dtype("uint32"), "I"),
(np.dtype("int64"), "l"),
(np.dtype("uint64"), "L"),
(np.dtype("float16"), "e"),
(np.dtype("float32"), "f"),
(np.dtype("float64"), "g"),
(pd.Series(["a"]).dtype, "u"),
(
pd.Series([0]).astype("datetime64[ns]").dtype,
"tsn:",
),
(pd.CategoricalDtype(["a"]), "l"),
(np.dtype("O"), "u"),
],
)
def test_dtype_to_arrow_c_fmt(pandas_dtype, c_string): # PR01
"""Test ``dtype_to_arrow_c_fmt`` utility function."""
assert dtype_to_arrow_c_fmt(pandas_dtype) == c_string
@pytest.mark.parametrize(
"pa_dtype, args_kwargs, c_string",
[
["null", {}, "n"],
["bool_", {}, "b"],
["uint8", {}, "C"],
["uint16", {}, "S"],
["uint32", {}, "I"],
["uint64", {}, "L"],
["int8", {}, "c"],
["int16", {}, "S"],
["int32", {}, "i"],
["int64", {}, "l"],
["float16", {}, "e"],
["float32", {}, "f"],
["float64", {}, "g"],
["string", {}, "u"],
["binary", {}, "z"],
["time32", ("s",), "tts"],
["time32", ("ms",), "ttm"],
["time64", ("us",), "ttu"],
["time64", ("ns",), "ttn"],
["date32", {}, "tdD"],
["date64", {}, "tdm"],
["timestamp", {"unit": "s"}, "tss:"],
["timestamp", {"unit": "ms"}, "tsm:"],
["timestamp", {"unit": "us"}, "tsu:"],
["timestamp", {"unit": "ns"}, "tsn:"],
["timestamp", {"unit": "ns", "tz": "UTC"}, "tsn:UTC"],
["duration", ("s",), "tDs"],
["duration", ("ms",), "tDm"],
["duration", ("us",), "tDu"],
["duration", ("ns",), "tDn"],
["decimal128", {"precision": 4, "scale": 2}, "d:4,2"],
],
)
def test_dtype_to_arrow_c_fmt_arrowdtype(pa_dtype, args_kwargs, c_string):
# GH 52323
pa = pytest.importorskip("pyarrow")
if not args_kwargs:
pa_type = getattr(pa, pa_dtype)()
elif isinstance(args_kwargs, tuple):
pa_type = getattr(pa, pa_dtype)(*args_kwargs)
else:
pa_type = getattr(pa, pa_dtype)(**args_kwargs)
arrow_type = pd.ArrowDtype(pa_type)
assert dtype_to_arrow_c_fmt(arrow_type) == c_string