From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: poffice@blade.nagaokaut.ac.jp Delivered-To: poffice@blade.nagaokaut.ac.jp Received: from kankan.nagaokaut.ac.jp (kankan.nagaokaut.ac.jp [133.44.2.24]) by blade.nagaokaut.ac.jp (Postfix) with ESMTP id 7992019C003A for ; Tue, 3 Nov 2015 14:53:02 +0900 (JST) Received: from voscc.nagaokaut.ac.jp (voscc.nagaokaut.ac.jp [133.44.1.100]) by kankan.nagaokaut.ac.jp (Postfix) with ESMTP id 5F97AB5D952 for ; Tue, 3 Nov 2015 15:21:42 +0900 (JST) Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by voscc.nagaokaut.ac.jp (Postfix) with ESMTP id 403E2952439 for ; Tue, 3 Nov 2015 15:21:41 +0900 (JST) Received: from [221.186.184.76] (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 33299120520; Tue, 3 Nov 2015 15:21:38 +0900 (JST) X-Original-To: ruby-core@ruby-lang.org Delivered-To: ruby-core@ruby-lang.org Received: from o2.heroku.sendgrid.net (o2.heroku.sendgrid.net [67.228.50.55]) by neon.ruby-lang.org (Postfix) with ESMTPS id 77CB71204EF for ; Tue, 3 Nov 2015 15:21:34 +0900 (JST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sendgrid.me; h=from:to:references:subject:mime-version:content-type:content-transfer-encoding:list-id; s=smtpapi; bh=uSu972ZoeZ/swJVrTirYooSSLAI=; b=YL8B1No+ZtGdEN77MZ 4khYsofYpfuEsA5zTiO70liRY65b0H0vBpMUuMQqCGzbv4G4/k2j2RtM5BXsjz3K OPVjIITNrsE9PBSBsyApZ2lMXeiIxYaLwxapLNYoG1xhSzAxjK20s6MNKbhGJ2+g ylxg4nOZJKR/fv2cCUtrwIUqI= Received: by filter0634p1mdw1.sendgrid.net with SMTP id filter0634p1mdw1.18529.5638526A1B 2015-11-03 06:21:30.44540495 +0000 UTC Received: from herokuapp.com (ec2-184-73-15-9.compute-1.amazonaws.com [184.73.15.9]) by ismtpd0003p1iad1.sendgrid.net (SG) with ESMTP id vCb90GvsTKuvpTJ5pczGew for ; Tue, 03 Nov 2015 06:21:30.229 +0000 (UTC) Date: Tue, 03 Nov 2015 06:21:30 +0000 From: matz@ruby-lang.org To: ruby-core@ruby-lang.org Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Redmine-MailingListIntegration-Message-Ids: 45945 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 11643 X-Redmine-Issue-Author: gkop X-Redmine-Sender: matz X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: ync6xU2WACa70kv/Ymy4QrNMhiuLXJG8OTL2vJD1yS5iE2Ks6rmywBIA1dPZuGpieV0B/f0pYR+TtD pTulo9JOiiUgYYKu9+xKQlhRu85HfOJe2JP3WuQX+oAIjswbPV5Z9PYNgT6l27a2aPFxFfflJHChbw AXCKBvT86aBh2v1Ja7IF2XrUjx7SGB+T0SJ4 X-ML-Name: ruby-core X-Mail-Count: 71307 Subject: [ruby-core:71307] [Ruby trunk - Feature #11643] A new method on Hash to grab values out of nested hashes, failing gracefully X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #11643 has been updated by Yukihiro Matsumoto. I prefer method way to (already reverted) `params.?[:order].?[:shipping_info].?[:country]`. I am not sure `dig` is the best name for it. It's short, concise thought. Any other idea, anyone? Matz. ---------------------------------------- Feature #11643: A new method on Hash to grab values out of nested hashes, failing gracefully https://bugs.ruby-lang.org/issues/11643#change-54682 * Author: Gabe Kopley * Status: Open * Priority: Normal * Assignee: ---------------------------------------- (I posted this to the mailing list last year [0] and received no response, but am inspired to file an issue here based on the positive reception to https://bugs.ruby-lang.org/issues/11537 ) This comes up sometimes in Rails programming [1]: `params[:order] && params[:order][:shipping_info] && params[:order][:shipping_info][:country]` or `params[:order][:shipping_info][:country] rescue nil` or `params.fetch(:order, {}).fetch(:shipping_info, {}).fetch(:country, nil)` What if Hash gave us a method to accomplish this more concisely and semantically? Eg. `params.traverse_nested_hashes_and_return_nil_if_a_key_isnt_found(:order, :shipping_info, :country)` Or to take a nice method name suggestion [2]: `params.dig(:order, :shipping_info, :country)` Another example solution is https://github.com/intridea/hashie#deepfetch (Although I don't like "fetch" in this method name since it doesn't and can't take a default value as an argument like Hash#fetch does) What do you all think? [0] https://groups.google.com/forum/#!topic/ruby-core-google/guleNgEJWcM [1] https://groups.google.com/d/msg/rubyonrails-core/bOkvcvS3t_A/QXLEXwt9ivAJ https://stackoverflow.com/questions/1820451/ruby-style-how-to-check-whether-a-nested-hash-element-exists https://stackoverflow.com/questions/19115838/how-do-i-use-the-fetch-method-for-nested-hash https://stackoverflow.com/questions/10130726/ruby-access-multidimensional-hash-and-avoid-access-nil-object [2] http://stackoverflow.com/a/1820492/283398 -- https://bugs.ruby-lang.org/