io.BytesIO

class io.BytesIO([initial_bytes])

A stream implementation using an in-memory bytes buffer. It inherits BufferedIOBase. The buffer is discarded when the close() method is called.

The optional argument initial_bytes is a bytes-like object that contains initial data.

BytesIO provides or overrides these methods in addition to those from BufferedIOBase and IOBase:

getbuffer()

Return a readable and writable view over the contents of the buffer without copying them. Also, mutating the view will transparently update the contents of the buffer:

>>> b = io.BytesIO(b"abcdef")
>>> view = b.getbuffer()
>>> view[2:4] = b"56"
>>> b.getvalue()
b'ab56ef'

Note

As long as the view exists, the BytesIO object cannot be resized or closed.

New in version 3.2.

getvalue()

Return bytes containing the entire contents of the buffer.

read1()

In BytesIO, this is the same as read().

readinto1()

In BytesIO, this is the same as readinto().

New in version 3.5.