Python 3.5, bytes, and %-interpolation (aka PEP 461)
steve+comp.lang.python at pearwood.info
Tue Feb 25 00:55:14 CET 2014
On Mon, 24 Feb 2014 11:54:54 -0800, Ethan Furman wrote:
> A PEP is under discussion to add %-interpolation back to the bytes type
> in Python 3.5.
> Assuming the PEP is accepted, what *will* be added back is:
> b'%d' % 10 --> b'10'
> b'%02x' % 10 --> b'0a'
> Single byte:
> b'%c' % 80 --> b'P'
Will %c also accept a length-1 bytes object?
b'%c' % b'x'
> and generic:
> b'%s' % some_binary_blob --> b'tHE*&92h4' (or whatever)
Will b'%s' take any arbitrary object, as in:
b'Key: %s' % [1, 2, 3, 4]
=> b'Key: [1, 2, 3, 4]'
or only something which is already bytes (i.e. a bytes or bytearray
> What is under debate is whether we should also add %a:
> b'%a' % some_obj --> b'some_obj_repr'
> What %a would do:
> get the repr of some_obj
> convert it to ascii using backslashreplace (to handle any code points
> over 127)
> encode to bytes using 'ascii'
> Can anybody think of a use-case for this particular feature?
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