This looks like JavaScript Object Notation (JSON). You can parse JSON that resides in some variable, e.g. json_string, like so: require ‘json’ JSON.parse(json_string) If you’re using an older Ruby, you may need to install the json gem. There are also other implementations of JSON for Ruby that may fit some use-cases better: YAJL C Bindings … Read more
This answer was edited multiple times and now contains several alternative solutions. Try the simple “Edit 3” solution first. Ruby 1.9.3-p125 and later have official support for clang, so if you are installing such a version you should not need GCC. If you’re installing an older version of Ruby, read on. To compile Ruby with … Read more
Here is how Matz(Yukihiro Matsumoto) explains it in an old thread: Hi, In message “[ruby-talk:02706] X++?” on 00/05/10, Aleksi Niemelä <aleksi.niemela@cinnober.com> writes: |I got an idea from http://www.pragprog.com:8080/rubyfaq/rubyfaq-5.html#ss5.3 |and thought to try. I didn’t manage to make “auto(in|de)crement” working so |could somebody help here? Does this contain some errors or is the idea |wrong? (1) … Read more
The * is the splat operator. It expands an Array into a list of arguments, in this case a list of arguments to the Hash.[] method. (To be more precise, it expands any object that responds to to_ary/to_a, or to_a in Ruby 1.9.) To illustrate, the following two statements are equal: method arg1, arg2, arg3 … Read more
You can create a simple patch on Symbol like this: class Symbol def with(*args, &block) ->(caller, *rest) { caller.send(self, *rest, *args, &block) } end end Which will enable you to do not only this: a = [1,3,5,7,9] a.map(&:+.with(2)) # => [3, 5, 7, 9, 11] But also a lot of other cool stuff, like passing … Read more
system The system method calls a system program. You have to provide the command as a string argument to this method. For example: >> system(“date”) Wed Sep 4 22:03:44 CEST 2013 => true The invoked program will use the current STDIN, STDOUT and STDERR objects of your Ruby program. In fact, the actual return value … Read more
Ruby uses the case expression instead. case x when 1..5 “It’s between 1 and 5” when 6 “It’s 6” when “foo”, “bar” “It’s either foo or bar” when String “You passed a string” else “You gave me #{x} — I have no idea what to do with that.” end Ruby compares the object in the … Read more
You may use the different accessors to communicate your intent to someone reading your code, and make it easier to write classes which will work correctly no matter how their public API is called. class Person attr_accessor :age … end Here, I can see that I may both read and write the age. class Person … Read more
Instance variable on a class: class Parent @things = [] def self.things @things end def things self.class.things end end class Child < Parent @things = [] end Parent.things << :car Child.things << :doll mom = Parent.new dad = Parent.new p Parent.things #=> [:car] p Child.things #=> [:doll] p mom.things #=> [:car] p dad.things #=> [:car] … Read more
First, the class << foo syntax opens up foo‘s singleton class (eigenclass). This allows you to specialise the behaviour of methods called on that specific object. a=”foo” class << a def inspect ‘”bar”‘ end end a.inspect # => “bar” a=”foo” # new object, new singleton class a.inspect # => “foo” Now, to answer the question: … Read more