I have this array right here and I need to get the "id" of each object
[{ id: 1, points: 60 }, { id: 2, points: 20 }, { id: 3, points: 95 }, { id: 4, points: 75 }]
customers = [{ id: 1, points: 90 }, { id: 2, points: 20 }, { id: 3, points: 70 }, { id: 4, points: 40 }, { id: 5, points: 60 }, { id: 6, points: 10}]
I know how to go through the whole array with
@scores.each_with_index{ |score, index| }
However, I haven't found a way to get the objects's points.
Perhaps you are looking for the following.
customers = [
{ id: 1, points: 90 }, { id: 2, points: 20 },
{ id: 3, points: 70 }, { id: 4, points: 40 },
{ id: 5, points: 60 }, { id: 6, points: 10}
]
h = customers.each_with_object({}) do |g,h|
id, points = g.values_at(:id, :points)
h[id] = points
end
#=> {1=>90, 2=>20, 3=>70, 4=>40, 5=>60, 6=>10}
This allows you to easily extract information of interest, such as the following.
h.keys
#=> [1, 2, 3, 4, 5, 6]
h.values
#=> [90, 20, 70, 40, 60, 10]
h[2]
#=> 20
h.key?(5)
#=> true
h.key?(7)
#=> false
h.value?(70)
#=> true
h.value?(30)
#=> false
What you called score is actually an hash like { id: 1, points: 60 } and I'm going to call it item
So, let's try
@scores.each_with_index do |item, index|
puts "#{index + 1}: id #{item[:id]}, points #{item[:points]}"
end
So, I have this array right here and I need to get the id of each object
In order to transform each element of a collection, you can use Enumerable#map (or in this case more precisely Array#map):
customers.map { _1[:id] }
#=> [1, 2, 3, 4, 5, 6]
This given construct is an array of objects so we need to individually iterate through each element and print out the value present in the objects. The following code shows how we can do it:
customers.each{|obj| p obj[:id].to_s+" "+ obj[:points].to_s }
Here we iterate through each element and print out individual entities of the hash using the obj[:id]/obj[:points] (obj being each individual object here.)
What about something like this?
customers.map(&:to_proc).map{ |p| [:id, :points].map(&p) }
=> [[1, 90], [2, 20], [3, 70], [4, 40], [5, 60], [6, 10]]
