CODEWITHSUNDEEP
ruby
Charles Nough
Charles Nough

Reputation: 365

(Ruby) Lottery Numbers, without duplicates

I got the task to create a lottery program which outputs 6 random numbers from 1 to 49 without duplicates. I'm not allowed to use the shuffle-Method of Arrays and as a tip I recieved that I should create an array with 49 entries and "shuffle" the numbers. I thought about this tip but it's not really helping.

This is what I got till now, I hope someone understands my code. I'm still stuck in a more Java way of writing than in ruby.

# Generating the Array
l_num = Array.new(6)
i = 0
while (i == 0)
    l_num << [rand(1...49), rand(1...49), rand(1...49), rand(1...49), rand(1...49), rand(1...49)]
    if (l_num.uniq.length == l_num.length)
        i += 1
    end
end
#Output
puts 'Todays lottery numbers are'
l_num.each { |a| print a, " " }

I picked up the uniq-Methode, because I read that it could elimante doubles that way, but I don't think it works in this case. In previous versions of my code I got a Error because I was trying to override the allready created array, I understand why Ruby is giving me an error but I have no clue how to do it in another way.

I hope someone is able to provide me some code-pieces, methods, solutions or tips for this task, thanks in advance.

Upvotes: 1

Views: 2013

Answers (4)

Ajay
Ajay

Reputation: 4251

min_lottery_number = 1 
max_lottery_number = 49 
total_size = 6 

(min_lottery_number..max_lottery_number).to_a.sample(total_size)

Upvotes: 0

Cary Swoveland
Cary Swoveland

Reputation: 110725

Here's one way to do it you can't use sample:

a = *1..49
  #=> [1, 2, 3,..., 49] 
6.times.map { a.delete_at(rand(a.size))+1 }
  # => [44, 41, 15, 19, 46, 17]

Upvotes: 2

nzifnab
nzifnab

Reputation: 16110

This is the strategy I would take:

lottery_numbers = []

begin
  # add 1 because otherwise it gives you numbers from 0-48
  number = rand(49)+1
  lottery_numbers.push(number) unless lottery_numbers.include?(number)
end while lottery_numbers.size < 6

puts "lottery numbers:"
puts lottery_numbers.join(" ")

Rubyists tend to initialize arrays with [] as opposed to the verbose Array.new

Upvotes: 4

oldhomemovie
oldhomemovie

Reputation: 15129

Charles, I think the easiest would be the following:

Array.new(49) { |x| x + 1 }.sample(6)

However this is what I believe you was prohibited to do? If yes, try a more "manual" solution:

Array.new(49) { |x| x + 1 }.sort { rand() - 0.5 }.take(6)

Otherwise, try implementing one completely "manual" solution. For example:

require 'set'

result = Set.new

loop do
  result << 1 + rand(49)
  break if result.size == 6
end

puts result.to_a.inspect

Upvotes: 2

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