CODEWITHSUNDEEP
ruby-on-railsruby
Charlie
Charlie

Reputation: 341

Return values were not extracted in Ruby

def get_dept_class_type
  departments, classifications, types = [["-- select one --"]] * 3

  Department.all.each do |d|
    departments << d.name
  end

  Classification.all.each do |c|
    classifications << c.name
  end

  Type.all.each do |t|
    types << t.name
  end

  return departments, classifications, types
end

def new
 @departments, @classifications, @types = get_dept_class_type
end

Hello guys,

above is my code in Ruby to assign the return values from "get_dept_class_type" function to "def new" instance variables. The problem is, the return values from the "get_dept_class_type" function were not extracted, So all instance variables have the same values. Each instance variable is the containing value of a select tag in html form.

The values of department, classification, type select tags have these the same content:

Please it help me to figure this out. Thank you in advanced.

Upvotes: 1

Views: 95

Answers (1)

Arup Rakshit
Arup Rakshit

Reputation: 118271

Your main problem is -

 departments, classifications, types = [["-- select one --"]] * 3

changed it to -

departments, classifications, types = Array.new(3) { ["-- select one --"] }

Lets debug it :-

([[]] * 3).map(&:object_id) # => [72506330, 72506330, 72506330]

but

Array.new(3) { [] }.map(&:object_id) # => [76642680, 76642670, 76642520]

You can see, that all the inner objects are basically same object. Basically you have created an array of array, say a, where all the element arrays are same object. Thus if you have modified, say a[0], you can see the same change when you would inspect a[1] or a[2]. But if you do create the same array of array, a as , Array.new(3) { [] }, then each inner element array of a, will be different object. Thus if you say modify a[0], then a[1] and a[2] will be intact.

Worth to read Common gotchas.

Upvotes: 3

Related Questions