from __future__ import annotations import gzip import io import tarfile from typing import ( TYPE_CHECKING, Any, ) import zipfile from pandas.compat._optional import import_optional_dependency import pandas as pd if TYPE_CHECKING: from collections.abc import Callable from pathlib import Path from pandas import ( DataFrame, Series, ) # ------------------------------------------------------------------ # File-IO def round_trip_pickle(obj: Any, tmp_path: Path) -> DataFrame | Series: """ Pickle an object and then read it again. Parameters ---------- obj : any object The object to pickle and then re-read. path : str, path object or file-like object, default None The path where the pickled object is written and then read. Returns ------- pandas object The original object that was pickled and then re-read. """ pd.to_pickle(obj, tmp_path) return pd.read_pickle(tmp_path) def round_trip_pathlib(writer, reader, tmp_path: Path): """ Write an object to file specified by a pathlib.Path and read it back Parameters ---------- writer : callable bound to pandas object IO writing function (e.g. DataFrame.to_csv ) reader : callable IO reading function (e.g. pd.read_csv ) path : str, default None The path where the object is written and then read. Returns ------- pandas object The original object that was serialized and then re-read. """ writer(tmp_path) obj = reader(tmp_path) return obj def write_to_compressed(compression, path: str, data, dest: str = "test") -> None: """ Write data to a compressed file. Parameters ---------- compression : {'gzip', 'bz2', 'zip', 'xz', 'zstd'} The compression type to use. path : str The file path to write the data. data : str The data to write. dest : str, default "test" The destination file (for ZIP only) Raises ------ ValueError : An invalid compression value was passed in. """ args: tuple[Any, ...] = (data,) mode = "wb" method = "write" compress_method: Callable if compression == "zip": compress_method = zipfile.ZipFile mode = "w" args = (dest, data) method = "writestr" elif compression == "tar": compress_method = tarfile.TarFile mode = "w" file = tarfile.TarInfo(name=dest) bytes = io.BytesIO(data) file.size = len(data) args = (file, bytes) method = "addfile" elif compression == "gzip": compress_method = gzip.GzipFile elif compression == "bz2": import bz2 compress_method = bz2.BZ2File elif compression == "zstd": compress_method = import_optional_dependency("zstandard").open elif compression == "xz": import lzma compress_method = lzma.LZMAFile else: raise ValueError(f"Unrecognized compression type: {compression}") # error: No overload variant of "ZipFile" matches argument types "str", "str" # error: No overload variant of "BZ2File" matches argument types "str", "str" # error: Argument "mode" to "TarFile" has incompatible type "str"; # expected "Literal['r', 'a', 'w', 'x'] with compress_method(path, mode=mode) as f: # type: ignore[call-overload, arg-type] getattr(f, method)(*args)