获得哈希

Question

我有这样的哈希值的数组，这是由价值:a分类的一个子：

[{:a=>0, :b=>10}, {:a=>0, :b=>35}, {:a=>1, :b=>20}, {:a=>2, :b=>0}] 

我怎样才能得到这个数组与最小值的散列的一个子集为:a？ 这里，:a最小值为0，所以我需要：

[{:a=>0, :b=>10}, {:a=>0, :b=>35}] 

Answer 1

对我来说似乎是公认的答案，使假设数组中的第一个元素的:a值最小。所以如果数组在第一个元素:a => 1处被修改，那么结果是不正确的。这里的例子：

# original 
z = [{:a=>0, :b=>10}, {:a=>0, :b=>35}, {:a=>1, :b=>20}, {:a=>2, :b=>0}] 
puts z.select{|y| y[:a] == z.first[:a]}.inspect 
# => [{:a=>0, :b=>10}, {:a=>0, :b=>35}] the result is the expected one 

# modified :a of first element 
z = [{:a=>1, :b=>10}, {:a=>0, :b=>35}, {:a=>1, :b=>20}, {:a=>2, :b=>0}] 
puts z.select{|y| y[:a] == z.first[:a]}.inspect 
# => [{:a=>1, :b=>10}, {:a=>1, :b=>20}] here result does not have min :a 

现在不做这种假设我正在寻找的:a

z = [{:a=>0, :b=>10}, {:a=>0, :b=>35}, {:a=>1, :b=>20}, {:a=>2, :b=>0}] 
# find the min :a 
m = z.map { |y| y[:a] }.min 
puts z.select{|y| y[:a] == m}.inspect 
# => [{:a=>0, :b=>10}, {:a=>0, :b=>35}] 

# modified :a of first element 
z = [{:a=>1, :b=>10}, {:a=>0, :b=>35}, {:a=>1, :b=>20}, {:a=>2, :b=>0}] 
m = z.map { |y| y[:a] }.min 
puts z.select{|y| y[:a] == m}.inspect 
# => [{:a=>0, :b=>35}] 

Answer 2

z = [{:a=>0, :b=>10}, {:a=>0, :b=>35}, {:a=>1, :b=>20}, {:a=>2, :b=>0}] 
z.select{|y| y[:a] == z.first[:a]}