Learn to Program, 2nd Edition

Random Numbers

Ruby comes with a pretty nice random number generator. The method to get a randomly chosen number is rand. If you call rand just like that, you’ll get a float greater than or equal to 0.0 and less than 1.0. If you give it an integer parameter (by calling rand(5), for example), it will give you an integer greater than or equal to 0 and less than 5 (so five possible numbers, from 0 to 4).

Let’s see rand in action:

puts rand
puts rand
puts rand
puts(rand(100))
puts(rand(100))
puts(rand(100))
puts(rand(1))
puts(rand(1))
puts(rand(1))
puts(rand(9999999999999999999999999999999999999))
puts('The weatherman said there is a')
puts(rand(101).to_s + '% chance of rain,')
puts('but you can never trust a weatherman.')

0.780420251671991
0.27612531216364 ...