From: Joey Zhou <yimutang@...>
Date: 2011-05-25T23:20:10+09:00
Subject: [ruby-core:36465] [Ruby 1.9 - Feature #4772] Hash#add_keys


Issue #4772 has been updated by Joey Zhou.


Rodrigo Rosenfeld Rosas wrote:
> Actually, as already noticed here, this could be just:
> 
> ['a', 'b', 'c'].each {|k| hash[k]} # You don't need to assign to it.

Well, it is very obscure here, easy to be confused.

1) hash = Hash.new {|h,k| k.succ }
2) hash = Hash.new {|h,k| h[k] = k.succ }

1) and 2) are different, 2) will actually create any key/value pair the hash ever seen a key, but 1) will not, it needs an assignment.

Joey
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Feature #4772: Hash#add_keys
http://redmine.ruby-lang.org/issues/4772

Author: Joey Zhou
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 


Hi, do you want to add a new method Hash#add_keys in a new version?

hash = Hash.new {|h,k| k.to_s + "foo" }
hash.add_keys("a","b","c") # the value is hash's default obj or proc value

If there's a word list file, I want to make the words keys of a hash, maybe I can write:

hash = {}
hash.add_keys(*open("file").readlines.map(&:chomp))




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