When I get exceptions, it is often from deep within the call stack. When this happens, more often than not, the actual offending line of code is hidden from me: tmp.rb:7:in `t’: undefined method `bar’ for nil:NilClass (NoMethodError) from tmp.rb:10:in `s’ from tmp.rb:13:in `r’ from tmp.rb:16:in `q’ from tmp.rb:19:in `p’ from tmp.rb:22:in `o’ from tmp.rb:25:in … Read more
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)) ? 8 Answers 8
In general, what are the advantages and disadvantages of using an OpenStruct as compared to a Struct? What type of general use-cases would fit each of these? 9 Answers 9
After running the bundle install command, ‘Gemfile.lock‘ is created in the working directory. What do the directives inside that file mean? For example, let’s take the following file: PATH remote: . specs: gem_one (0.0.1) GEM remote: http://example.org/ specs: gem_two (0.0.2) gem_three (0.0.3) gem_four (0.0.4) PLATFORMS platform DEPENDENCIES gem_two gem_one! What do ‘PATH‘, ‘GEM‘, ‘PLATFORMS‘ and … Read more
I read https://stackoverflow.com/questions/826734/when-do-ruby-instance-variables-get-set but I’m of two minds when to use class instance variables. Class variables are shared by all objects of a class, Instance variables belong to one object. There’s not much room left to use class instance variables if we have class variables. Could someone explain the difference between these two and when … Read more
Background: I have a module which declares a number of instance methods module UsefulThings def get_file; … def delete_file; … def format_text(x); … end And I want to call some of these methods from within a class. How you normally do this in ruby is like this: class UsefulWorker include UsefulThings def do_work format_text(“abc”) … … Read more
I’m new to Ruby and don’t know how to add new item to already existing hash. For example, first I construct hash: hash = {item1: 1} after that a want to add item2 so after this I have hash like this: {item1: 1, item2: 2} I don’t know what method to do on hash, could … Read more
I have a large hash with nested arrays and hashes. I would like to simply print it out so it ‘readable’ to the user. I would like it to be sort of like to_yaml – that’s pretty readable – but still too tech looking. Ultimately its going to be end users who need to read … Read more
I would like to test whether a class inherits from another class, but there doesn’t seem to exist a method for that. class A end class B < A end B.is_a? A => false B.superclass == A => true A trivial implementation of what I want would be: class Class def is_subclass_of?(clazz) return true if … Read more
It’s easy enough to read a CSV file into an array with Ruby but I can’t find any good documentation on how to write an array into a CSV file. Can anyone tell me how to do this? I’m using Ruby 1.9.2 if that matters. 6 Answers 6
