http://blog.randomutterings.com/articles/2008/01/09/fixed-length-random-numbers-in-ruby en-us 40 <p>My latest project is almost complete and we're setting up a demo site with lots of fake data already included so I used the faker gem to generate most of it.</p> <p>One issue I had that I couldn't do with the faker gem out of the box is get a fixed length random number. I need this for license numbers, credit card numbers, phone numbers and others. The faker gem does offer a random phone number but the ones in my project don't support extensions or punctuation so rather than generating the number then using string functions to strip out the stuff I didn't want, I decided to find an easier way.</p> <p>I started by Googling for it assuming that someone else had already figured it out and while I'm sure its been done a hundred times before, I couldn't find it anywhere. So after much thought and digging through the ruby docs, this is what I came up with.</p> <blockquote> <code> rand(9999999999).to_s.center(10, rand(9).to_s) </code> </blockquote> <p>rand(9999999999) will give me a number between 0 and 9999999999. Convert it to a string and use the center method to make sure its at least 10 digits long and pad the rest with a random number from 0-9. rand(9)</p> <p>If you need a number of say 7 digits in length, just change the first rand to rand(9999999) and change the center method length to 7 so it looks like this.</p> <blockquote> <code> rand(9999999).to_s.center(7, rand(9).to_s) </code> </blockquote> <p>Hope this is helpful to someone.</p> Wed, 09 Jan 2008 11:20:00 -0500 urn:uuid:3d11eeca-de64-42c7-86ea-9f74999c2057 Chris Barnes http://blog.randomutterings.com/articles/2008/01/09/fixed-length-random-numbers-in-ruby Ruby ruby random numbers faker gem http://blog.randomutterings.com/articles/trackback/26 Just what i needed, thanks. Tue, 05 Aug 2008 15:27:05 -0400 urn:uuid:44b58245-f246-485e-90fd-6b23d3b51c55 http://blog.randomutterings.com/articles/2008/01/09/fixed-length-random-numbers-in-ruby#comment-2547 If you want to make this a function based on length, one way to get that initial "9999999" would be the expression: ("9" * length).to_i Sun, 06 Jul 2008 00:44:09 -0400 urn:uuid:0e078428-9ce4-4514-9a74-6d8ecc99785b http://blog.randomutterings.com/articles/2008/01/09/fixed-length-random-numbers-in-ruby#comment-2415 Very nice.. Thanks for the tip. :) Sat, 05 Jul 2008 01:21:25 -0400 urn:uuid:7417b00a-754d-4213-9ec5-4c5a3d05f1fb http://blog.randomutterings.com/articles/2008/01/09/fixed-length-random-numbers-in-ruby#comment-2408