如何从哈希数组中过滤出哈希？

Question

I have params that looks like this:

params = [{:limit=>5}, {:skip=>0}, {:asc=>""}, {:desc=>""}]

I want to remove the hash elements whose value is 0 or an empty string. I tried doing:

params.reject { |h| h.values !== 0 }

but this gives me a syntax error

Also tried:

params.select { |h| h.values != 0 || h.values != "" }

but this gives me nothing. What am I doing wrong?

Answer 1

You have an array of hashes, so you have to operate on each hash.

params.reject { |hash| hash.any? { |_, v| [0, ''].include?(v) }}
#=> [{:limit=>5}]

Answer 2

Instead of having an array of hashes with only one pair of |key,value| , you could just merge all the hashes to get one big hash.

It becomes easier to remove the unwanted values, and it also becomes easier to extract information :

params = [{ limit: 5 }, { skip: 0 }, { asc: '' }, { desc: '' }]

hash = params.inject(&:merge).reject{|_, value| value == 0 || value == '' }
# => {:limit=>5}

hash[:limit]
# => 5

With an array of hashes, you'd have to write :

(h = array_of_hashes.find{|h| h.keys.include?(:limit)} ) && h[:limit]
#=> 5

Answer 3

I found two ways to do this:

filtered = params.reject { |hash| hash.values.any? { |v| v.to_i == 0 } }

and

filtered = params.select { |hash| hash.values.none? { |val| val == '' || val == 0 } }

Answer 4

使用带有include的拒绝也将解决此问题。

 params.reject { |key| key.values.include?(0) || key.values.include?("") }