Go equivalent of Python's io.BytesIO

io.BytesIO in Python 3.x provides a convenient way of having a file-like object that actually streams to/from memory.

In Go, the equivalent problem is to have a io.Reader and/or and io.Writer (i.e. the equivalent of Python’s file-like object) that is backed by a []byte or a string.

Solution: Use bytes.Buffer !

// Initialize an empty buffer (e.g. for writing)
buf := &bytes.Buffer{}

// Initialize a buffer with a []byte content (e.g. for reading)
myBytes := ...
buf := bytes.NewBuffer(myBytes)

// Initialize a buffer with string
myStr := "test 123"
buf := bytes.NewBufferString(myStr)