io

The io module provides the Python interfaces to stream handling. The builtin open function is defined in this module.

At the top of the I/O hierarchy is the abstract base class IOBase. It defines the basic interface to a stream. Note, however, that there is no separation between reading and writing to streams; implementations are allowed to raise an OSError if they do not support a given operation.

Extending IOBase is RawIOBase which deals simply with the reading and writing of raw bytes to a stream. FileIO subclasses RawIOBase to provide an interface to OS files.

BufferedIOBase deals with buffering on a raw byte stream (RawIOBase). Its subclasses, BufferedWriter, BufferedReader, and BufferedRWPair buffer streams that are readable, writable, and both respectively. BufferedRandom provides a buffered interface to random access streams. BytesIO is a simple stream of in-memory bytes.

Another IOBase subclass, TextIOBase, deals with the encoding and decoding of streams into text. TextIOWrapper, which extends it, is a buffered text interface to a buffered raw stream (BufferedIOBase). Finally, StringIO is an in-memory stream for text.

Argument names are not part of the specification, and only the arguments of open() are intended to be used as keyword arguments.

data:

DEFAULT_BUFFER_SIZE

An int containing the default buffer size used by the module’s buffered I/O classes. open() uses the file’s blksize (as obtained by os.stat) if possible.

Functions

open(file[, mode, buffering, encoding, ...])	Open file and return a stream.
open_code(path)	Opens the provided file with the intent to import the contents.
text_encoding(encoding[, stacklevel])	A helper function to choose the text encoding.

Classes

BlockingIOError	I/O operation would block.
IOBase	The abstract base class for all I/O classes.
RawIOBase	Base class for raw binary I/O.
FileIO(file[, mode, closefd, opener])	Open a file.
BytesIO([initial_bytes])	Buffered I/O implementation using an in-memory bytes buffer.
StringIO([initial_value, newline])	Text I/O implementation using an in-memory buffer.
BufferedIOBase	Base class for buffered IO objects.
BufferedReader(raw[, buffer_size])	Create a new buffered reader using the given readable raw IO object.
BufferedWriter(raw[, buffer_size])	A buffer for a writeable sequential RawIO object.
BufferedRWPair(reader, writer[, buffer_size])	A buffered reader and writer object together.
BufferedRandom(raw[, buffer_size])	A buffered interface to random access streams.
TextIOBase	Base class for text I/O.
TextIOWrapper(buffer[, encoding, errors, ...])	Character and line based layer over a BufferedIOBase object, buffer.
UnsupportedOperation
IncrementalNewlineDecoder(decoder, translate)	Codec used when reading a file in universal newlines mode.