From: naruse@airemix•jp
To: ruby-dev@ruby-lang.org
Subject: [ruby-dev:50758] [Ruby trunk Feature#6118][Feedback] Hash#keys_of(values), returns related keys of given values
Date: Thu, 10 Jan 2019 08:16:08 +0000 (UTC) [thread overview]
Message-ID: <redmine.journal-76194.20190110081607.4618400fb435afd0@ruby-lang.org> (raw)
In-Reply-To: redmine.issue-6118.20120306175507@ruby-lang.org
Issue #6118 has been updated by naruse (Yui NARUSE).
Status changed from Assigned to Feedback
I forgot use case.
use case is welcome
----------------------------------------
Feature #6118: Hash#keys_of(values), returns related keys of given values
https://bugs.ruby-lang.org/issues/6118#change-76194
* Author: naruse (Yui NARUSE)
* Status: Feedback
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version:
----------------------------------------
Hash#key(value) の複数版がほしいです。
{a: 1, b: 2, c: 3, d: 1}.key(1)
=> :a
というメソッドはあるのですが、
{a: 1, b: 2, c: 3, d: 1}.keys_of(1)
=> [:a, :d]
というメソッドは現状ありません。
Ruby での実装例は以下のような感じになります。
どうでしょうか。
class Hash
def keys_of(*a)
each_with_object([]) {|(k, v), r| r << k if a.include? v}
end
end
---Files--------------------------------
000_ruby_hash_keys_of.patch (2.36 KB)
000_ruby_hash_keys_of.patch (2.36 KB)
--
https://bugs.ruby-lang.org/
prev parent reply other threads:[~2019-01-10 8:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-06 8:55 [ruby-dev:45310] [ruby-trunk - Feature #6118][Open] Hash#keys_of(values), returns related keys of given values Yui NARUSE
2012-03-26 16:38 ` [ruby-dev:45438] [ruby-trunk - Feature #6118] " ssuda (Sambasiva Suda)
2012-03-26 16:44 ` [ruby-dev:45439] " ssuda (Sambasiva Suda)
2012-03-29 16:54 ` [ruby-dev:45457] [ruby-trunk - Feature #6118][Assigned] " mame (Yusuke Endoh)
2012-11-20 13:18 ` [ruby-dev:46563] [ruby-trunk - Feature #6118] " mame (Yusuke Endoh)
2019-01-10 8:16 ` naruse [this message]
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