如何在哈希中获取min键值对

I want to fetch the lowest value in the hash.

我想获取哈希中的最低值。

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?

我怎样才能得到预期的结果?

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

我需要所有最小的键/值对。如果{'a'=> 1,'b'=> 1,'c'=> 2},预期结果应为{'a'=> 1,'b'=> 1}。

4 个解决方案

#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}

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

#2

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

To make it more efficient:

为了提高效率:

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

#3

AS Per Given Your Data

根据您的数据

Run the following on your Ruby Console :-

在Ruby控制台上运行以下命令: -

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

产量将按照您的预期

 => {"f"=>0.02}

#4

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

您也可以在不使用.min方法的情况下实现此目的:

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!!!

我必须为我正在上课的课程做类似的事情。我们还必须返回JUST THE KEY。为什么你会做同样的事情只返回测试[0] [0]希望这是有帮助的!

#1

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