[ACCEPTED]-Is there a way to initialize an object through a hash?-initialization

Accepted answer

Score: 54

You can define an initialize function on 3 your class:

class A
  attr_accessor :b,:c,:d
  def initialize(h)
    h.each {|k,v| public_send("#{k}=",v)}
  end
end

Or you can create a module and 2 then "mix it in"

module HashConstructed
 def initialize(h)
  h.each {|k,v| public_send("#{k}=",v)}
 end
end

class Foo
 include HashConstructed
 attr_accessor :foo, :bar
end

Alternatively 1 you can try something like constructor

Score: 18

OpenStructis worth considering:

require 'ostruct' # stdlib, no download
the_hash = {"b"=>10, "c"=>20, "d"=>30}
there_you_go = OpenStruct.new(the_hash)
p there_you_go.c #=> 20

Score: 10

instance_variable_set is intended for this kind of use case:

class A
  def initialize(h)
    h.each {|k,v| instance_variable_set("@#{k}",v)}
  end
end

It's 7 a public method, so you could also call 6 it after construction:

a = A.new({})
a.instance_variable_set(:@foo,1)

But note the implied 5 warning in the documentation:

Sets the instance variable 4 names by symbol to object, thereby frustrating 3 the efforts of the class’s author to attempt 2 to provide proper encapsulation. The variable 1 did not have to exist prior to this call.

Source: stackoverflow.com

call parent constructor in ruby

Java: how to initialize child when super constructor requires parameter

Calling instance method during initialization in Swift

const reference must be initialized in constructor base/member initializer list

C++ - Run a function before initializing a class member

Initialize array or vector over constructor's initializing list

Why is int x = int(5) legal if int is not a class?

Initialize() vs Constructor() method, proper usage on object creation

Dilemma in calling constructor of generic class

Why doesn't Java have initializer lists like in C++?

Cookie Warning

We use cookies to improve the performance of the site. By staying on our site, you agree to the terms of use of cookies.