I have an array of hashes from which I need the values of the hashes in a new array. The array of hashes look likes this, with a couple thousand of them.
array = [{:code=>"404"}, {:code=>"302"}, {:code=>"200"}]
I have tried to look this up but have only found out how to convert from a hash.
How would I go about doing this?
[{:code=>"404"}, {:code=>"302"}, {:code=>"200"}].flat_map(&:values)
#⇒ ["404", "302", "200"]
a=[{:code=>"404"}, {:code=>"302"}, {:code=>"200"}]
puts a.map{|x|x.values}.flatten.inspect
output
["404", "302", "200"]
map followed by flatten, consider using flat_map instead.arr =[{:code=>"404"}, {:code=>"302"}, {:code=>"200"}]
arr.map { |h| h[:code] }
#=> ["404", "302", "200"]
or, if the name of the key (now :code) might change in future:
arr.map { |h| h.first.last }
#=> ["404", "302", "200"]
h.first converts hash key,value as array.
{a: 1, b: 2}.each { |a| p a } prints [:a, 1] then [:b, 2].first is a method in the Enumerable module. That module is included by the class Hash. All methods in Enumerable require that the receiver be an enumerator. When first is called on a hash, Ruby (after seeing that there is no method Hash#first and knowing that Enumerable#first requires an enumerator) inserts the instance method Hash#each: {a: 1}.first is evaluated as {a: 1}.each.first. That's why all classes that include Enumerable must have a method each that returns an enumerator.each method is from enumerator class but it can be called upon array like a.each, but a is not an enumerator object, So it contradict with what you said, right?This question is tagged with ruby only.
But I think it might be worth noting that, when you happen to use Ruby on Rails or have the activesupport gem in your Gemfile anyway, then you might want to use Enumerable#pluck:
array = [{:code=>"404"}, {:code=>"302"}, {:code=>"200"}]
array.pluck(:code)
#=> ["404", "302", "200"]
array.flat_map { |h| h.values }