How to get min key value pair in hash

Question

I want to fetch the lowest value in the hash.

Input:

test = {'a'=> 1, 'b'=> 2, 'c' => 0.4, 'd' => 0.32, 'e' => 0.03, 'f' => 0.02, 'g'=> 0.1}

Expected result:

{'f'=> 0.02}

How can I get the expected result?

I need all minimum key/value pairs. if {'a'=>1,'b'=>1,'c'=>2} the expected result should be {'a'=>1,'b'=>1}.

Weinert

What do you want to do if there are multiple minimum values? – Favin

i need all minimum key/value pairs. if {'a'=>1,'b'=>1,'c'=>2}. the expected result is {'a'=>1,'b'=>1} – Weinert

Answer 1

[test.min_by{|k, v| v}].to_h

---

Answer to the question after it has been changed:

test.group_by{|k, v| v}.min_by{|k, v| k}.last.to_h # => {"f"=>0.02}

or

test.group_by(&:last).min_by(&:first).last.to_h # => {"f"=>0.02}

Quitt

Answer 2

test.select { |_, v| v == test.values.min }

To make it more efficient:

min_val = test.values.min
test.select { |_, v| v == min_val }

Ragwort

Answer 3

AS Per Given Your Data

Run the following on your Ruby Console :-

test = {'a'=> 1, 'b'=> 2, 'c' => 0.4, 'd' => 0.32, 'e' => 0.03,
'f' => 0.02, 'g'=> 0.1}

Hash[*test.sort_by(&:last)[0]]

Output will be as per per your expectations

 => {"f"=>0.02} 

Rummage

REVIEW of low quality post: Please format your code better. Write some explanation of proposed solution as well. In the current form this answer is likely to be deleted for moderation reasons. I'm not voting for deletion only because it seems to be a good path to solve the problem. Someone else might not be so generous. – Clostridium

Answer 4

You can also achieve this without using a .min method:

def min_key_value_pair (test)
  if test == {}
       return nil
  else
       test = test.sort_by {|k, v| v}
       test[0]
   end
end

I had to do something similar for a class I am taking. We also had to return JUST THE KEY. for which you would do the same thing only return test[0][0] Hope this was helpful!!!

Tav