[Python-ideas] Add an option for delimiters in bytes.hex()

David Mertz mertz at gnosis.cx
Tue May 2 13:48:08 EDT 2017

On Tue, May 2, 2017 at 4:31 AM, Steven D'Aprano <steve at pearwood.info> wrote:

> Rather than duplicate the API and logic everywhere, I suggest we add a
> new string method. My suggestion is str.chunk(size, delimiter=' ') and
> str.rchunk() with the same arguments:
> "1234ABCDEF".chunk(4)
> => returns "1234 ABCD EF"
> rchunk will be useful for money or other situations where we group from
> the right rather than from the left:
> "$" + str(10**6).rchunk(3, ',')
> => returns "$1,000,000"
> # Format mobile phone number in the Australian style
> "04123456".rchunk((4, 3))
> => returns "0412 345 678"
> # Format an integer in the Indian style
> str(123456789).rchunk((3, 2), ",")
> => returns "12,34,56,789"

I like this general idea very much.  Dealing with lakh and crore is a very
nice feature (and one that the `.format()` mini-language sadly fails to
handle; it assumes numeric delimiters can only be commas, and only ever
three positions).

But I'm not sure the semantics you propose is flexible enough.  I take it
that the tuple means (<first-delimiter>, <other-delimiters>) from your
examples.  But I don't think that suffices for every common format.  It
would be fine to get a USA phone number like:

    str(4135559414).rchunk((4,3),'-')  # -> 413-555-9414

But for example, looking somewhat at random at an international call (

*Dialing from New York to Brussel**011-32-2-555-12-12* - Omitting the
leading "0".

Maybe your API is for any length tuple, with the final element repeated.
So I guess maybe this example could be:


I don't care about this method being called .chunk() vs. .delimit() vs.
something else.

Keeping medicines from the bloodstreams of the sick; food
from the bellies of the hungry; books from the hands of the
uneducated; technology from the underdeveloped; and putting
advocates of freedom in prisons.  Intellectual property is
to the 21st century what the slave trade was to the 16th.
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