[#50466] [ruby-trunk - Bug #7492][Open] Segmentation fault at DL::TestDL#test_call_double on x64 Windows 8 — "phasis68 (Heesob Park)" <phasis@...>
23 messages
2012/12/02
[#59083] [ruby-trunk - Bug #7492] Segmentation fault at DL::TestDL#test_call_double on x64 Windows 8
— "phasis68 (Heesob Park)" <phasis@...>
2013/12/13
[#50483] [IMPORTANT] 2.0.0 release plan — Yusuke Endoh <mame@...>
ALL COMMITTERS SHOULD READ THIS MAIL! コミッタはこのメール読んで！
5 messages
2012/12/02
[#50561] [ruby-trunk - Bug #7513][Open] TracePoint#enable/disable should not cause error — "ko1 (Koichi Sasada)" <redmine@...>
7 messages
2012/12/05
[#50575] [ruby-trunk - Feature #7517][Open] Fixnum::MIN,MAX — "matz (Yukihiro Matsumoto)" <matz@...>
20 messages
2012/12/05
[#50593] [ruby-trunk - Feature #7517] Fixnum::MIN,MAX
— "shyouhei (Shyouhei Urabe)" <shyouhei@...>
2012/12/05
[#50594] Re: [ruby-trunk - Feature #7517] Fixnum::MIN,MAX
— Charles Oliver Nutter <headius@...>
2012/12/05
On Wed, Dec 5, 2012 at 12:24 PM, shyouhei (Shyouhei Urabe)
[#50636] [ruby-trunk - Bug #7528][Open] CSV.== fails to check object type — "SteveW (Stephen Wattam)" <stephenwattam@...>
6 messages
2012/12/06
[#50645] [ruby-trunk - Bug #7530][Open] Concurrent loads fail with mutex errors — "headius (Charles Nutter)" <headius@...>
7 messages
2012/12/06
[#50660] [ruby-trunk - Feature #4085] Refinements and nested methods — "trans (Thomas Sawyer)" <transfire@...>
3 messages
2012/12/07
[#50699] Commit access for Yehuda Katz — Aaron Patterson <tenderlove@...>
Hi,
4 messages
2012/12/08
[#50923] Re: Commit access for Yehuda Katz
— Charles Oliver Nutter <headius@...>
2012/12/16
I will +1 this, unsure if it has happened already (it's "catch up on
[#50733] [ruby-trunk - Bug #7539][Open] Misleading error message "can't convert nil into string" — "connec (Chris Connelly)" <chris@...>
8 messages
2012/12/10
[#50755] Becoming a committer — Charlie Somerville <charlie@...>
Hi ruby-core,
21 messages
2012/12/11
[#50759] Re: Becoming a committer
— Yukihiro Matsumoto <matz@...>
2012/12/11
Hi,
[#50784] Re: Becoming a committer
— Charles Oliver Nutter <headius@...>
2012/12/11
It's really this easy? If so, I'll send over my public key today :)
[#50795] Re: Becoming a committer
— Yukihiro Matsumoto <matz@...>
2012/12/11
Hi,
[#50797] Re: Becoming a committer
— Charles Oliver Nutter <headius@...>
2012/12/11
I guess there's a few things I'd be interested in:
[#50809] Re: Becoming a committer
— SASADA Koichi <ko1@...>
2012/12/12
(2012/12/12 8:55), Charles Oliver Nutter wrote:
[#50815] Re: Becoming a committer
— Charles Oliver Nutter <headius@...>
2012/12/12
On Wed, Dec 12, 2012 at 12:04 AM, SASADA Koichi <[email protected]> wrote:
[#50816] Re: Becoming a committer
— "NARUSE, Yui" <naruse@...>
2012/12/12
2012/12/12 Charles Oliver Nutter <[email protected]>:
[#50817] Re: Becoming a committer
— Charles Oliver Nutter <headius@...>
2012/12/12
On Wed, Dec 12, 2012 at 2:59 AM, NARUSE, Yui <[email protected]> wrote:
[#50765] [ruby-trunk - Bug #7544][Open] Accented characters in IRB — cfabianski (Cédric FABIANSKI) <cfabianski@...>
6 messages
2012/12/11
[#50793] [ruby-trunk - Bug #7547][Open] Dir.mktmpdir('~something') tries to expand a profile directory — "jstanley0 (Jeremy Stanley)" <jeremy@...>
4 messages
2012/12/11
[#50810] [ruby-trunk - Feature #7549][Open] A Ruby Design Process — "brixen (Brian Ford)" <brixen@...>
34 messages
2012/12/12
[#50829] [ruby-trunk - Feature #7549] A Ruby Design Process
— "subwindow (Erik Peterson)" <erik@...>
2012/12/12
[#50837] [ruby-trunk - Feature #7549] A Ruby Design Process
— "subwindow (Erik Peterson)" <erik@...>
2012/12/12
[#50867] [ruby-trunk - Bug #7556][Assigned] test error on refinement — "usa (Usaku NAKAMURA)" <usa@...>
14 messages
2012/12/13
[#50900] [ruby-trunk - Bug #7564][Open] r38175 introduces incompatibility — "tenderlovemaking (Aaron Patterson)" <aaron@...>
14 messages
2012/12/14
[#50913] [ruby-trunk - Bug #7568][Open] Yaml fails to encode zero date string. — "anshul (Anshul Khandelwal)" <anshul@...>
5 messages
2012/12/15
[#50920] [ruby-trunk - Bug #7568][Assigned] Yaml fails to encode zero date string.
— "charliesome (Charlie Somerville)" <charlie@...>
2012/12/16
[#50988] Re: [ruby-trunk - Bug #7568][Assigned] Yaml fails to encode zero date string.
— Aaron Patterson <tenderlove@...>
2012/12/19
On Sun, Dec 16, 2012 at 12:53:14PM +0900, charliesome (Charlie Somerville) wrote:
[#51015] 1.9.3 patch level release — Zachary Scott <zachary@...>
I know unak-san was asking about a 1.9.3 patch level release, so I
8 messages
2012/12/20
[#51099] [ruby-trunk - Feature #7612][Open] Enumerators take a proc — "pedz (Perry Smith)" <pedz@...>
4 messages
2012/12/23
[ruby-core:50534] [ruby-trunk - Feature #7444] Array#product_set
From:
"stomar (Marcus Stollsteimer)" <redmine@...>
Date:
2012-12-03 17:51:05 UTC
List:
ruby-core #50534
Issue #7444 has been updated by stomar (Marcus Stollsteimer).
Thanks and sorry for being unclear.
It seemed to me that you did not specify the expected behavior for the proposed method in the case of e.g. 3 arrays.
----------------------------------------
Feature #7444: Array#product_set
https://bugs.ruby-lang.org/issues/7444#change-34377
Author: marcandre (Marc-Andre Lafortune)
Status: Open
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: next minor
I'd like to propose `Array#product_set` to return the product set of arrays (aka cartesian product)
deck = [1..13, %i(spades hearts diamond clubs)].product_set
# => <#Enumerator ...>
deck.first(2) # => [[1, :spades], [2, :spades]]
`product_set` would return an enumerator if no block is given. It should raise an error if an element of the array is not an Enumerable, like Array#transpose or #zip do.
Although `Array.product` would be acceptable too, I feel that an instance method of array is best in the case, in the same way that `transpose` is an instance method and not a class method.
The name "product_set" is a correct mathematical term. Although the synonym "cartesian_product" would also be acceptable, I propose "product_set" because it is shorter and cute too. I feel it is even clearer than `product`; the first time I head of `product` I was convinced that `[2,3,7].product # => 42`.
Addressing objections raised in #6499:
1) This is not for the sake of symmetry, but because often we have an array of the arrays we want a product of.
It is cumbersome to write `arrays.first.product(*arrays[1..-1])` or similar and it hides what is going on.
Writing `arrays.product_set` is much nicer.
2) The goal is not mainly to get a lazy version, but more to make the API better. The fact that it returns an Enumerator if no block is given is just a bonus :-)
3) [].product_set.to_a # => [[]]
This can be seen from a cardinality argument, or for example because `array.repeated_permutation(n) == Array.new(n, array).product_set.to_a` and `array.repeated_permutation(0) == [[]]`.
--
http://bugs.ruby-lang.org/
