projektAI/venv/Lib/site-packages/pandas/io/sas/sasreader.py
2021-06-06 22:13:05 +02:00

153 lines
4.3 KiB
Python

"""
Read SAS sas7bdat or xport files.
"""
from abc import ABCMeta, abstractmethod
from typing import TYPE_CHECKING, Optional, Union, overload
from pandas._typing import FilePathOrBuffer, Label
from pandas.io.common import stringify_path
if TYPE_CHECKING:
from pandas import DataFrame
# TODO(PY38): replace with Protocol in Python 3.8
class ReaderBase(metaclass=ABCMeta):
"""
Protocol for XportReader and SAS7BDATReader classes.
"""
@abstractmethod
def read(self, nrows=None):
pass
@abstractmethod
def close(self):
pass
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
self.close()
@overload
def read_sas(
filepath_or_buffer: FilePathOrBuffer,
format: Optional[str] = ...,
index: Optional[Label] = ...,
encoding: Optional[str] = ...,
chunksize: int = ...,
iterator: bool = ...,
) -> ReaderBase:
...
@overload
def read_sas(
filepath_or_buffer: FilePathOrBuffer,
format: Optional[str] = ...,
index: Optional[Label] = ...,
encoding: Optional[str] = ...,
chunksize: None = ...,
iterator: bool = ...,
) -> Union["DataFrame", ReaderBase]:
...
def read_sas(
filepath_or_buffer: FilePathOrBuffer,
format: Optional[str] = None,
index: Optional[Label] = None,
encoding: Optional[str] = None,
chunksize: Optional[int] = None,
iterator: bool = False,
) -> Union["DataFrame", ReaderBase]:
"""
Read SAS files stored as either XPORT or SAS7BDAT format files.
Parameters
----------
filepath_or_buffer : str, path object or file-like object
Any valid string path is acceptable. The string could be a URL. Valid
URL schemes include http, ftp, s3, and file. For file URLs, a host is
expected. A local file could be:
``file://localhost/path/to/table.sas``.
If you want to pass in a path object, pandas accepts any
``os.PathLike``.
By file-like object, we refer to objects with a ``read()`` method,
such as a file handle (e.g. via builtin ``open`` function)
or ``StringIO``.
format : str {'xport', 'sas7bdat'} or None
If None, file format is inferred from file extension. If 'xport' or
'sas7bdat', uses the corresponding format.
index : identifier of index column, defaults to None
Identifier of column that should be used as index of the DataFrame.
encoding : str, default is None
Encoding for text data. If None, text data are stored as raw bytes.
chunksize : int
Read file `chunksize` lines at a time, returns iterator.
.. versionchanged:: 1.2
``TextFileReader`` is a context manager.
iterator : bool, defaults to False
If True, returns an iterator for reading the file incrementally.
.. versionchanged:: 1.2
``TextFileReader`` is a context manager.
Returns
-------
DataFrame if iterator=False and chunksize=None, else SAS7BDATReader
or XportReader
"""
if format is None:
buffer_error_msg = (
"If this is a buffer object rather "
"than a string name, you must specify a format string"
)
filepath_or_buffer = stringify_path(filepath_or_buffer)
if not isinstance(filepath_or_buffer, str):
raise ValueError(buffer_error_msg)
fname = filepath_or_buffer.lower()
if fname.endswith(".xpt"):
format = "xport"
elif fname.endswith(".sas7bdat"):
format = "sas7bdat"
else:
raise ValueError("unable to infer format of SAS file")
reader: ReaderBase
if format.lower() == "xport":
from pandas.io.sas.sas_xport import XportReader
reader = XportReader(
filepath_or_buffer,
index=index,
encoding=encoding,
chunksize=chunksize,
)
elif format.lower() == "sas7bdat":
from pandas.io.sas.sas7bdat import SAS7BDATReader
reader = SAS7BDATReader(
filepath_or_buffer,
index=index,
encoding=encoding,
chunksize=chunksize,
)
else:
raise ValueError("unknown SAS format")
if iterator or chunksize:
return reader
with reader:
return reader.read()