io.IOBase¶

class io.IOBase[source]¶

The abstract base class for all I/O classes, acting on streams of bytes. There is no public constructor.

This class provides dummy implementations for many methods that derived classes can override selectively; the default implementations represent a file that cannot be read, written or seeked.

Even though IOBase does not declare read, readinto, or write because their signatures will vary, implementations and clients should consider those methods part of the interface. Also, implementations may raise a IOError when operations they do not support are called.

The basic type used for binary data read from or written to a file is the bytes type. Method arguments may also be bytearray or memoryview of arrays of bytes. In some cases, such as readinto, a writable object such as bytearray is required. Text I/O classes work with unicode data.

Note that calling any method (except additional calls to close(), which are ignored) on a closed stream should raise a ValueError.

IOBase (and its subclasses) support the iterator protocol, meaning that an IOBase object can be iterated over yielding the lines in a stream.

IOBase also supports the with statement. In this example, fp is closed after the suite of the with statement is complete:

with open(‘spam.txt’, ‘r’) as fp:

fp.write(‘Spam and eggs!’)