arr = [{"title"=>"iPhone", "value_percent"=>"42.6"}, {"title"=>"Windows 7", "value_percent"=>"21.3"}, {"title"=>"Android", "value_percent"=>"12.8"}, {"title"=>"Mac OS X", "value_percent"=>"8.5"}, {"title"=>"Windows 8.1", "value_percent"=>"6.4"}, {"title"=>"Windows XP", "value_percent"=>"4.3"}, {"title"=>"Linux", "value_percent"=>"2.1"}, {"title"=>"Windows Vista", "value_percent"=>"2.1"}] 
 
hash = {}
arr.each do |i|
   key = i["title"]
   value = i["value_percent"]
   hash[key] = value
end
 
p hash
 
hash = Hash[arr.map do |v| [v["title"], v["value_percent"]] end]
 
p hash

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