[Python-Dev] Why does base64 return bytes? (original) (raw)

Random832 random832 at fastmail.com
Tue Jun 14 14:02:02 EDT 2016

On Tue, Jun 14, 2016, at 13:19, Paul Sokolovsky wrote:

Well, it's easy to remember the conclusion - it was decided to return bytes. The reason also wouldn't be hard to imagine - regardless of the fact that base64 uses ASCII codes for digits and letters, it's still essentially a binary data.

Only in the sense that all text is binary data. There's nothing in the definition of base64 specifying ASCII codes. It specifies characters that all happen to be in ASCII's character repertoire.

And the most natural step for it is to send it down the socket (socket.send() accepts bytes), etc.

How is that more natural than to send it to a text buffer that is ultimately encoded (maybe not even in an ASCII-compatible encoding... though probably) and sent down a socket or written to a file by a layer that is outside your control? Yes, everything eventually ends up as bytes. That doesn't mean that we should obsessively convert things to bytes as early as possible.

I mean if we were gonna do that why bother even having a unicode string type at all?

I'd find it a bit more surprising that binascii.hexlify() returns bytes, but I personally got used to it, and consider it a consistency thing on binascii module.

Generally, with Python3 by default using (inefficient) Unicode for strings,

Why is it inefficient?

any efficient data processing would use bytes, and then one appreciates the fact that data encoding/decoding routines also return bytes, avoiding implicit expensive conversion to strings.

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