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# pandas.read_hdf

pandas.read_hdf(path_or_buf, key=None, mode='r', errors='strict', where=None, start=None, stop=None, columns=None, iterator=False, chunksize=None, **kwargs)

  Read from the store, close it if we opened it.

  Retrieve pandas object stored in file, optionally based on where criteria. This function requires the PyTables library.

  Note

  This function only reads HDF5 files written by pandas (via `DataFrame.to_hdf()`, `Series.to_hdf()`, or `HDFStore`), which use a pandas-specific layout built on PyTables. Arbitrary HDF5 files produced by other tools such as `h5py` or plain PyTables are not supported; use those libraries directly to read such files.

  Warning

  Pandas uses PyTables for reading and writing HDF5 files, which allows serializing object-dtype data with pickle when using the “fixed” format. Loading pickled data received from untrusted sources can be unsafe.

  See: https://docs.python.org/3/library/pickle.html for more.

  Parameters:
    path_or_buf str, path object, pandas.HDFStore

      Any valid string path is acceptable. Only supports the local file system, remote URLs and file-like objects are not supported.

      If you want to pass in a path object, pandas accepts any `os.PathLike`.

      Alternatively, pandas accepts an open `pandas.HDFStore` object.

    key object, optional

      The group identifier in the store. Can be omitted if the HDF file contains a single pandas object.

    mode{‘r’, ‘r+’, ‘a’}, default ‘r’

      Mode to use when opening the file. Ignored if path_or_buf is a `pandas.HDFStore`. Default is ‘r’.

    errors str, default ‘strict’

      Specifies how encoding and decoding errors are to be handled. See the errors argument for `open()` for a full list of options.

    where list, optional

      A list of Term (or convertible) objects.

    start int, optional

      Row number to start selection.

    stop int, optional

      Row number to stop selection.

    columns list, optional

      A list of columns names to return.

    iterator bool, optional

      Return an iterator object.

    chunksize int, optional

      Number of rows to include in an iteration when using an iterator.

    **kwargs

      Additional keyword arguments passed to HDFStore.

  Returns:
    object

      The selected object. Return type depends on the object stored.

  See also

  `DataFrame.to_hdf`

    Write an HDF file from a DataFrame.

  `HDFStore`

    Low-level access to HDF files.

  Notes

  When `errors="surrogatepass"`, `pd.options.future.infer_string` is true, and PyArrow is installed, if a UTF-16 surrogate is encountered when decoding to UTF-8, the resulting dtype will be `pd.StringDtype(storage="python", na_value=np.nan)`.

  Examples

      >>> df = pd.DataFrame([[1, 1.0, "a"]], columns=["x", "y", "z"])
      >>> df.to_hdf("./store.h5", "data")
      >>> reread = pd.read_hdf("./store.h5")