How to get a random number in Ruby

Simplest answer to the question:

rand(0..n)

you can do rand(range)

x = rand(1..5)

Maybe it help you. I use this in my app

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class String

# Create a random String of given length, using given character set
#
# Character set is an Array which can contain Ranges, Arrays, Characters
#
# Examples
#
# String.random
# => "D9DxFIaqR3dr8Ct1AfmFxHxqGsmA4Oz3"
#
# String.random(10)
# => "t8BIna341S"
#
# String.random(10, ['a'..'z'])
# => "nstpvixfri"
#
# String.random(10, ['0'..'9'] )
# => "0982541042"
#
# String.random(10, ['0'..'9','A'..'F'] )
# => "3EBF48AD3D"
#
# BASE64_CHAR_SET = ["A".."Z", "a".."z", "0".."9", '_', '-']
# String.random(10, BASE64_CHAR_SET)
# => "xM_1t3qcNn"
#
# SPECIAL_CHARS = ["!", "@", "#", "$", "%", "^", "&", "*", "(", ")", "-", "_", "=", "+", "|", "/", "?", ".", ",", ";", ":", "~", "`", "[", "]", "{", "}", "<", ">"]
# BASE91_CHAR_SET = ["A".."Z", "a".."z", "0".."9", SPECIAL_CHARS]
# String.random(10, BASE91_CHAR_SET)
# => "S(Z]z,J{v;"
#
# CREDIT: Tilo Sloboda
#
# SEE:
#
# TODO: Move to random.rb in standard library?

def self.random(len=32, character_set = ["A".."Z", "a".."z", "0".."9"])
chars = character_set.map{|x| x.is_a?(Range) ? x.to_a : x }.flatten
Array.new(len){ chars.sample }.join
end

end

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It works fine for me

How about this one?

num = Random.new
num.rand(1..n)

range = 10..50

**rand(range)**

or

**range.to_a.sample**

or

**range.to_a.shuffle**(this will shuffle whole array and you can pick a random number by first or last or any from this array to pick random one)

You can simply use `random_number`.

If a positive integer is given as n, `random_number` returns an integer: 0 <= `random_number` < n.

Use it like this:

any_number = SecureRandom.random_number(100)

The output will be any number between 0 and 100.

Easy way to get random number in ruby is,

def random
(1..10).to_a.sample.to_s
end

Use [`rand(range)`][1]

From [Ruby Random Numbers][2]:

> If you needed a random integer to simulate a roll of a six-sided die, you'd use: `1 + rand(6)`. A roll in craps could be simulated with `2 + rand(6) + rand(6)`.
>
> Finally, if you just need a random float, just call `rand` with no arguments.

----------

As [Marc-André Lafortune][3] mentions in [his answer below (go upvote it)][4], [Ruby 1.9.2 has its own `Random` class][5] (that Marc-André himself [helped to debug][6], hence the [1.9.2 target][7] for that feature).

For instance, in this [game where you need to guess 10 numbers][8], you can initialize them with:

10.times.map{ 20 + Random.rand(11) }
#=> [26, 26, 22, 20, 30, 26, 23, 23, 25, 22]

Note:

- Using `Random.new.rand(20..30)` (using `Random.new`) generally would not be a good idea, as explained in detail (again) by [Marc-André Lafortune][9], in [his answer][10] (again).

- But if you don't use `Random.new`, then the [class method `rand`][11] only takes a `max` value, not a `Range`, as [banister][12] (energetically) points out in the comment (and as documented in the [docs for `Random`][13]). Only the [instance method][14] can take a `Range`, as illustrated by

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.

This is why the equivalent of `Random.new.rand(20..30)` would be `20 + Random.rand(11)`, since `Random.rand(int)` returns “a random integer greater than or equal to zero and *less than the argument*.” `20..30` includes 30, I need to come up with a random number between 0 and 11, excluding 11.


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You can use ruby [rand][1] method for this like below:

rand(n+1)

You need to use `n+1` as the rand method returns any random number greater than or equal to 0 but less than the passed parameter value.


[1]:

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