How to generate a random number between a and b in Ruby?

ruby random range
Misha Moroshko picture Misha Moroshko · Dec 9, 2010 · Viewed 119.8k times · Source

To generate a random number between 3 and 10, for example, I use: rand(8) + 3

Is there a nicer way to do this (something like rand(3, 10)) ?

Answer

Nakilon picture Nakilon · Dec 9, 2010

UPDATE: Ruby 1.9.3 Kernel#rand also accepts ranges 

rand(a..b)

http://www.rubyinside.com/ruby-1-9-3-introduction-and-changes-5428.html

Converting to array may be too expensive, and it's unnecessary.

(a..b).to_a.sample

Or

[*a..b].sample

Array#sample

Standard in Ruby 1.8.7+.
Note: was named #choice in 1.8.7 and renamed in later versions.

But anyway, generating array need resources, and solution you already wrote is the best, you can do.

Related questions

How to get a random number in Ruby

How do I generate a random number between 0 and n?

Read More
How to generate a random string in Ruby

I'm currently generating an 8-character pseudo-random uppercase string for "A" .. "Z": value = ""; 8.times{value << (65 + rand(25)).chr} but it doesn't look clean, and it can't be passed as an argument since it isn't a single statement. To get a …

Read More
How do I pick randomly from an array?

I want to know if there is a much cleaner way of doing this. Basically, I want to pick a random element from an array of variable length. Normally, I would do it like this: myArray = ["stuff", "widget", "ruby", "goodies", "…

Read More