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

Question

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

User · Answer

For 10 and 10  24  rand 10  24-10  10

User · Answer

Just note the difference between the range operators   3  10    includes 10 3   10   doesn t include 10

User · Answer

def random int min  max      rand max - min    min end

User · Answer

See this answer  there is in Ruby 1 9 2  but not in earlier versions  Personally I think rand 8    3 is fine  but if you re interested check out the Random class described in the link

User · Answer

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

User · Answer

rand 3  10    Kernel rand     When max is a Range  rand returns a random number where range member  number     true

User · Answer

Random new rand a  b     Where a is your lowest value and b is your highest value

User · Answer

And here is a quick benchmark for both  sample and  rand   irb main  014 0  Benchmark bm do  x  irb main  015 1    x report  sample     1 000 000 times    1  100  to a sample     irb main  016 1 gt    x report  rand     1 000 000 times   rand 1  100      irb main  017 1 gt  end        user     system      total        real sample  3 870000   0 020000   3 890000    3 888147  rand  0 150000   0 000000   0 150000    0 153557    So  doing rand a  b  is the right thing

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

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