CODEWITHSUNDEEP
ruby
easyjo
easyjo

Reputation: 734

shift values from hash keys

I have this value {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

And I'm looking to retrieve/shift values from each key:

ie:

get the following:

[{:cat => "cat1", :dog => "dog1"}, {:cat => "cat2", :dog => "dog2"} ... etc]

I'm really not sure the best way to approach this, any suggestions?

Edit:

So far I have:

a[a.keys.first].dup.map{|c| a.map{|index, vals| vals.shift}}   
# => [["cat1", "dog1"], ["cat2", "dog2"], ["cat3", "dog3"]]

Though not quite what I want due to lack of keys.

Upvotes: 1

Views: 698

Answers (4)

sawa
sawa

Reputation: 168121

h = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

ks = h.keys
h.values.transpose.map{|vs| Hash[[ks, vs].transpose]}
# => [
#   {:cat => "cat1", :dog => "dog1"},
#   {:cat => "cat2", :dog => "dog2"},
#   {:cat => "cat3", :dog => "dog3"}
# ]

Or, strongly pushing a one-liner, slightly sacrificing the speed:

h.values.transpose.map{|vs| Hash[[h.keys, vs].transpose]}

Upvotes: 1

AJcodez
AJcodez

Reputation: 34186

Doesn't modify original hash:

h = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

h.values.first.zip(h.values.last).map do |value_pair| 
  Hash[ h.keys.zip(value_pair) ]
end

# => [{:cat=>"cat1", :dog=>"dog1"}, {:cat=>"cat2", :dog=>"dog2"}, {:cat=>"cat3", :dog=>"dog3"}]

h
# => {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

Array#zip: http://www.ruby-doc.org/core-1.9.3/Array.html#method-i-zip

Upvotes: 1

alex
alex

Reputation: 3742

cats_and_dogs = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

cats_with_dogs = []
i = 0
cats_and_dogs[:cat].each do |e|
    cats_with_dogs << {cat: cats_and_dogs[:cat][i], dog: cats_and_dogs[:dog][i]}
    i+=1
end

cats_with_dogs # [{:cat=>"cat1", :dog=>"dog1"}, {:cat=>"cat2", :dog=>"dog2"}, {:cat=>"cat3", :dog=>"dog3"}]

Upvotes: 0

Sergio Tulentsev
Sergio Tulentsev

Reputation: 230366

What about this?

a = {:cat=>["cat1", "cat2", "cat3"], :dog=>["dog1", "dog2", "dog3"]}

a1 = a.each_with_object({}) do |(k, vals), memo|
  shifted = vals.shift
  memo[k] = shifted
end

a # => {:cat=>["cat2", "cat3"], :dog=>["dog2", "dog3"]}
a1 # => {:cat=>"cat1", :dog=>"dog1"}

Upvotes: 3

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