Feature #8951: Please add a hash-to-hash alternative of the map method to Hash

• Status: Closed
• Assignee: -
• Target version: -

[behrangsa (Behrang Saeedzadeh)]

Please see this thread: https://twitter.com/behrangsa/status/382670159086776323

[fuadksd (Fuad Saud)]

Wow, I missed this a couple of days ago. Totally supported.

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Fuad Saud
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On Wednesday, September 25, 2013 at 1:05 AM, behrangsa (Behrang Saeedzadeh) wrote:

Issue #8951 has been reported by behrangsa (Behrang Saeedzadeh).

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Feature #8951: Please add a hash-to-hash alternative of the map method to Hash
https://bugs.ruby-lang.org/issues/8951

Author: behrangsa (Behrang Saeedzadeh)
Status: Open
Priority: Normal
Assignee:
Category:
Target version:

Please see this thread: https://twitter.com/behrangsa/status/382670159086776323

--
http://bugs.ruby-lang.org/

[jamonholmgren (Jamon Holmgren)]

How about:

Hash#graph

or

Hash#rehash

[fuadksd (Fuad Saud)]

#rehash is taken: http://www.ruby-doc.org/core-2.0.0/Hash.html#method-i-rehash

I was thinking about 'projection' or something, but everything feels just like an alternative to 'map' (#map, in my opinion, should return a hash).

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Fuad Saud
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On Wednesday, September 25, 2013 at 1:36 AM, jamonholmgren (Jamon Holmgren) wrote:

Issue #8951 has been updated by jamonholmgren (Jamon Holmgren).

How about:

Hash#graph

or

Hash#rehash

---

Feature #8951: Please add a hash-to-hash alternative of the map method to Hash
https://bugs.ruby-lang.org/issues/8951#change-41971

Author: behrangsa (Behrang Saeedzadeh)
Status: Open
Priority: Normal
Assignee:
Category:
Target version:

Please see this thread: https://twitter.com/behrangsa/status/382670159086776323

--
http://bugs.ruby-lang.org/

In my private library, I have 3 map-like methods defined on hash:

Hash#with_keys
Hash#with_values
Hash#modify

They work like this:

h = { a: 1, b: 2 }
h.with_keys do |k| k.to_s end #=> { "a"=>1, "b"=>2 }
h.with_values do |v| v.to_s end #=> { a: "1", b: "2" }
h.modify do |k, v| [k, "#{k}#{v}"] end #=> { a: "a1", b: "b2" }

plus their ! versions that modify the hash in place:

Hash#with_keys!, Hash#with_values!, Hash#modify!

But, this much being said, I am not sure whether this feature creep is such a good thing. Part of the fun in Ruby is that you are inventing your own libraries. If everything simple is already done in advance, it will be more "work" memorizing and less "fun" inventing :-))) Just randomly saying whatever comes to my mind, don't take me too seriously :-)

[behrangsa (Behrang Saeedzadeh)]

How about having a construct similar to map.with_index? For example map.to_has or map.hashify:

hash = { ... }
hash.map.to_hash do |e|
 convert(e)
end

or

hash = { ... }
hash.map.hashify do |e|
 convert(e)
end

[fuadksd (Fuad Saud)]

Hash#transform might also be a good name.

[Ajedi32 (Andrew M)]

I believe this is a duplicate of #6669

[shyouhei (Shyouhei Urabe)]

• Related to Feature #12512: Import Hash#transform_values and its destructive version from ActiveSupport added

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed