accessing variables outside block

Question

I have this code:

grades = ["Slect", "Choice", "Prime"]
names = grades.map{ |j| j.downcase }
names.zip(grades) do |r,n|
    r = Steak.new
    r.grade = n
    r
end

ObjectSpace.each_object(Steak) {|x| p x}

shows that Steak has 3 instances and grades get correct values assigned.

But I can't access choice for example outside the block.

any solutions?

Answer 1

Normally you approach this by doing a series of transforms that build up data. Your alterations to r are ignored, that's just reassigning a local variable that's later discarded since you don't actually attach it to anything.

The better way is to return this as a Hash with the right key:

class Steak
  attr_accessor :grade
end

grades = [ "Select", "Choice", "Prime" ]

map = Hash[
  grades.map do |grade|
    steak = Steak.new
    steak.grade = grade.downcase

    [ grade, steak ]
  end
]

# => {"Select"=>#<Steak:0x007fc6ef01bd60 @grade="select">, "Choice"=>#<Steak:0x007fc6ef01bcc0 @grade="choice">, "Prime"=>#<Steak:0x007fc6ef01bc20 @grade="prime">}

The only way to "access variables outside a block" is to make sure the block returns the data, or to have the variables defined prior to the block so they're part of the closure.