When I use sort_by on the frequency hash, it returns an array. How do I return a hash instead?
puts frequency.class #returns hash
frequency = frequency.sort_by {|k,v| v}.reverse
puts frequency.class #returns array
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2 Answers
sort_by just returns an array. You can cast it back to a hash like this:
frequency = frequency.sort_by {|k,v| v}.reverse
frequency = Hash[frequency]
7 Comments
Joshua Cheek
I don't think I'd call that casting, but yeah, this is the solution.
Jim Stewart
This doesn't work for me in 1.9.3. The hash 'order' (via
each) changes, but it's not sorted.
fmendez
@JimStewart That approach works fine for me under
ruby 1.9.3. I tried this code for instance: h = {:fernando => 28,:john => 18,:peter => 54} Hash[h.sort_by { |name, age| age }.reverse]fmendez
That's the correct result. See the
.reverse at the end. It would give you the values order by age starting by the oldest onto the youngest.
Mischa
For me it works in both 1.9.3 and 2.0.0. @JimStewart, you are talking about keys, but asker seems to want to sort on values. Which is what fmendez' example does too: a reverse sort on age.
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This is a pretty old question, but using Ruby 2.2+ it's pretty simple:
frequency.sort_by { |_, v| -v }.to_h
