From: Nicolas Petton <nicolas@petton.fr>
To: Oleh Krehel <ohwoeowho@gmail.com>
Cc: Nicolas Petton <nicolas@petton.fr>,
Stefan Monnier <monnier@iro.umontreal.ca>,
emacs-devel <emacs-devel@gnu.org>
Subject: Re: Would seq-range and seq-mapcat be useful?
Date: Mon, 02 Feb 2015 10:28:24 +0100 [thread overview]
Message-ID: <87d25s64sn.fsf@petton.fr> (raw)
In-Reply-To: <8761bk3g87.fsf@gmail.com>
Oleh Krehel <ohwoeowho@gmail.com> writes:
> Nicolas Petton <nicolas@petton.fr> writes:
>
>> Oleh Krehel <ohwoeowho@gmail.com> writes:
>>
>>> I'd like to have this:
>>>
>>> (defun seq-group-by (fn lst)
>>> (nreverse
>>> (cl-reduce
>>> (lambda (acc it)
>>> (let* ((key (funcall fn it))
>>> (cell (assoc key acc)))
>>> (if cell
>>> (setcdr cell (push it (cdr cell)))
>>> (push (list key it) acc))
>>> acc))
>>> lst
>>> :initial-value nil)))
>>>
>>> (seq-group-by
>>> #'car
>>> '(("a" 1)
>>> ("b" 2)
>>> ("b" 5)
>>> ("c" 1)))
>>> ;; (("a" ("a" 1))
>>> ;; ("b" ("b" 5)
>>> ;; ("b" 2))
>>> ;; ("c" ("c" 1)))
>>> (seq-group-by
>>> #'cadr
>>> '(("a" 1)
>>> ("b" 2)
>>> ("b" 5)
>>> ("c" 1)))
>>> ;; ((1 ("c" 1)
>>> ;; ("a" 1))
>>> ;; (2 ("b" 2))
>>> ;; (5 ("b" 5)))
>>>
>>> Is this already somewhere?
>>
>> I don't think it is :)
>>
>> I think I'm going with the following 3 additions to seq.el: `seq-mapcat',
>> `seq-group-by', and `seq-slice' (or `seq-partition'?).
>>
>> What do you think?
>>
>
> I like `seq-group-by`.
>
> I'm not sure about `seq-mapcat`, since there is `cl-mapcan` (although
> it's destructive), I guess `seq-mapcat` would be fine.
>
> And I would prefer the name `seq-partition` instead of `seq-slice`,
> since `partition' is a Clojure name with same effect, and slice means
> something different in Python.
Yes, I felt the same.
Nico
--
Nicolas Petton
http://nicolas-petton.fr
next prev parent reply other threads:[~2015-02-02 9:28 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-29 16:54 Would seq-range and seq-mapcat be useful? Nicolas Petton
2015-01-29 18:02 ` Artur Malabarba
2015-01-29 22:03 ` Nicolas Petton
2015-01-29 21:40 ` Stefan Monnier
2015-01-29 22:06 ` Nicolas Petton
2015-01-30 6:09 ` Stefan Monnier
2015-01-30 8:00 ` Oleh Krehel
2015-01-30 10:21 ` Nicolas Petton
2015-01-30 15:38 ` Oleh Krehel
2015-01-30 15:59 ` Nicolas Richard
2015-01-30 16:04 ` Oleh Krehel
2015-01-30 16:05 ` Oleh Krehel
2015-01-30 16:36 ` Nicolas Richard
2015-01-30 16:51 ` Oleh Krehel
2015-01-30 16:23 ` Nicolas Petton
2015-02-02 0:11 ` Nicolas Petton
2015-02-02 7:49 ` Oleh Krehel
2015-02-02 9:28 ` Nicolas Petton [this message]
2015-02-02 18:34 ` Mark Oteiza
2015-02-02 18:39 ` Oleh Krehel
2015-02-04 12:02 ` Ted Zlatanov
2015-01-30 8:20 ` What about seq-slice? (Was: Would seq-range and seq-mapcat be useful?) Mark Oteiza
2015-01-30 10:25 ` Nicolas Petton
2015-01-30 11:09 ` seq-thread-first/last (was: What about seq-slice?) Michael Heerdegen
2015-01-30 11:59 ` Nicolas Petton
2015-01-30 12:08 ` seq-thread-first/last Michael Heerdegen
2015-01-30 12:21 ` seq-thread-first/last Nicolas Petton
2015-01-30 12:17 ` seq-thread-first/last David Kastrup
2015-01-30 12:25 ` seq-thread-first/last Nicolas Petton
2015-01-30 12:33 ` seq-thread-first/last Michael Heerdegen
2015-01-30 12:58 ` seq-thread-first/last Bozhidar Batsov
2015-01-30 14:02 ` seq-thread-first/last Artur Malabarba
2015-01-30 14:15 ` seq-thread-first/last Michael Heerdegen
2015-01-30 17:17 ` What about seq-slice? Mark Oteiza
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