How to convert a 2D array to a value object in ruby - arrays

Question

I have a 2D array:
a = [["john doe", "01/03/2017", "01/04/2017", "event"], ["jane doe", "01/05/2017", "01/06/2017", "event"]...]
I would like to convert it to a value object in ruby. I found how to do it with a hash Ruby / Replace value in array of hash in the second answer of this question but not a 2D array. I would like to assign the value at a[0][0] to an attribute named "name", a[0][1] to "date1", a[0][2] to "date2" and a[0][3] to "event".
This is something like what I'd like to accomplish although it is not complete and I dont know how to assign multiple indexes to the different attributes in one loop:
class Schedule_info
arrt_accessor :name, :date1, :date2, :event
def initialize arr
#I would like this loop to contain all 4 attr assignments
arr.each {|i| instance_variable_set(:name, i[0])}

Answer 1

This should be short and clean enough, without unneeded metaprogramming :
data = [["john doe", "01/03/2017", "01/04/2017", "event"],
["jane doe", "01/05/2017", "01/06/2017", "event"]]
class ScheduleInfo
attr_reader :name, :date1, :date2, :type
def initialize(*params)
#name, #date1, #date2, #type = params
end
def to_s
format('%s for %s between %s and %s', type, name, date1, date2)
end
end
p info = ScheduleInfo.new('jane', '31/03/2017', '01/04/2017', 'party')
# #<ScheduleInfo:0x00000000d854a0 #name="jane", #date1="31/03/2017", #date2="01/04/2017", #type="party">
puts info.name
# "jane"
schedule_infos = data.map{ |params| ScheduleInfo.new(*params) }
puts schedule_infos
# event for john doe between 01/03/2017 and 01/04/2017
# event for jane doe between 01/05/2017 and 01/06/2017

Answer 2

You can't store the key value pairs in array index. Either you need to just remember that first index of array is gonna have "name" and assign a[0][0] = "foo" or just use array of hashes for the key value functionality you want to have
2.3.0 :006 > a = []
=> []
2.3.0 :007 > hash1 = {name: "hash1name", date: "hash1date", event: "hash1event"}
=> {:name=>"hash1name", :date=>"hash1date", :event=>"hash1event"}
2.3.0 :008 > a << hash1
=> [{:name=>"hash1name", :date=>"hash1date", :event=>"hash1event"}]
2.3.0 :009 > hash2 = {name: "hash2name", date: "hash2date", event: "hash2event"}
=> {:name=>"hash2name", :date=>"hash2date", :event=>"hash2event"}
2.3.0 :010 > a << hash2
=> [{:name=>"hash1name", :date=>"hash1date", :event=>"hash1event"}, {:name=>"hash2name", :date=>"hash2date", :event=>"hash2event"}]

Answer 3

It sounds like you want to call the attribute accessor method that corresponds to each array value. You use send to call methods programmatically. So you need an array of the method names that corresponds to the values you have in your given array. Now, assuming the class with your attributes is called Data.
attrs = [:name, :date1, :date2, :event]
result = a.map do |e|
d = Data.new
e.each.with_index do |v, i|
d.send(attrs[i], v)
end
d
end
The value result is an array of Data objects populated from your given array.
Of course, if you control the definition of your Data object, the best things would be to give it an initialize method that takes an array of values.

Answer 4

Try this:
class Schedule_info
arrt_accessor :name, :date1, :date2, :event
def initialize arr
#name = []
#date1 = []
#date2 = []
#event = []
arr.each |i| do
name << i[0]
date1 << i[1]
date2 << i[2]
event << i[3]
end
end
end