Well, I think the reason this is the case is because qwerty = 4 is ambiguous—are you defining a new variable called qwerty or calling the setter? Ruby resolves this ambiguity by saying it will create a new variable, thus the self. is required. Here is another case where you need self.: class A def … Read more
TL;DR: Use StandardError instead for general exception catching. When the original exception is re-raised (e.g. when rescuing to log the exception only), rescuing Exception is probably okay. Exception is the root of Ruby’s exception hierarchy, so when you rescue Exception you rescue from everything, including subclasses such as SyntaxError, LoadError, and Interrupt. Rescuing Interrupt prevents … Read more
Let’s say you have a class Person. class Person end person = Person.new person.name # => no method error Obviously we never defined method name. Let’s do that. class Person def name @name # simply returning an instance variable @name end end person = Person.new person.name # => nil person.name = “Dennis” # => no … Read more
First, note that this behavior applies to any default value that is subsequently mutated (e.g. hashes and strings), not just arrays. It also applies similarly to the populated elements in Array.new(3) { [] }. TL;DR: Use Hash.new { |h, k| h[k] = [] } if you want the most idiomatic solution and don’t care why. … Read more
It’s shorthand for tags.map(&:name.to_proc).join(‘ ‘) If foo is an object with a to_proc method, then you can pass it to a method as &foo, which will call foo.to_proc and use that as the method’s block. The Symbol#to_proc method was originally added by ActiveSupport but has been integrated into Ruby 1.8.7. This is its implementation: class … 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
Try: > ‘gmail.test.com’.split(‘.’).last(2) == [‘test’,’com’] => true
There are a few things to consider in addition to the comments above about the elementary part of the question. This is money. You’re using floats (“to_f“) but they are not accurate; Google for details. Ruby provides alternatives. For example, require ‘bigdecimal’ and then use BigDecimal.new(self.total_seconds.to_s) instead of self.total_seconds.to_f. BigDecimal is a sledgehammer – slow … Read more
You create instance of Encrypted method, but you set @code = 2, @string = “Hello” and @encrypted = []. So if you call @encrypted[0], ruby return nil. So you can modify your class like this: class Encrypt def initialize(code, string) @code, @string, @encrypted = code, string, [] end def to_byte @string.each_byte { |c| @encrypted << … Read more
It always helps if you include the error. There are two ways to fix that error: Interpolate the value: puts “you would like #{number} much better” Turn it from a number to a string: puts “you would like ” + number.to_s + ‘much better’ The former, #{…} syntax, evaluates the content of the braces as … Read more