How do I generate a random number between 0 and n? 17 s 17 Use rand(range) From Ruby Random Numbers: 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 … Read more
I am using the Ruby on Rails 3.1 pre version. I like to use PostgreSQL, but the problem is installing the pg gem. It gives me the following error: $ gem install pg Building native extensions. This could take a while… ERROR: Error installing pg: ERROR: Failed to build gem native extension. /home/u/.rvm/rubies/ruby-1.9.2-p0/bin/ruby extconf.rb checking … Read more
I have the following migration file db\migrate\20100905201547_create_blocks.rb How can I specifically rollback that migration file? 15 s 15 rake db:rollback STEP=1 Is a way to do this, if the migration you want to rollback is the last one applied. You can substitute 1 for however many migrations you want to go back. For example: rake … Read more
I’m getting the error: FATAL: Peer authentication failed for user “postgres” when I try to make postgres work with Rails. Here’s my pg_hba.conf, my database.yml, and a dump of the full trace. I changed authentication to md5 in pg_hba and tried different things, but none seem to work. I also tried creating a new user … Read more
I am running into some issues regarding the Authenticity Token in Rails. I would really like to understand the Authenticity token. Do you have some complete source of information on this subject or would you spend your time to explain in details here? 10 s 10 What happens When the user views a form to … Read more
How can I get the current absolute URL in my Ruby on Rails view? The request.request_uri only returns the relative URL. 33 s 33
Closed. This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 3 years ago. Improve this question I’m a beginner RoR programmer who’s planning to deploy my app using Heroku. Word from my … Read more
I find myself repeatedly looking for a clear definition of the differences of nil?, blank?, and empty? in Ruby on Rails. Here’s the closest I’ve come: blank? objects are false, empty, or a whitespace string. For example, “”, ” “, nil, [], and {} are blank. nil? objects are instances of NilClass. empty? objects are … Read more
I wrongly named a column hased_password instead of hashed_password. How do I update the database schema, using migration to rename this column? 3 31
