Is the line of code below valid Ruby code? -> (a) {p a}[“Hello world”] Yes, it’s valid. Here’s how to understand what it does: The -> operator is often called the “stabby proc”, and in ruby, it creates a new Proc, which is one of Ruby’s function types. It’s also…

Given: x = “hello” Can you explain the difference between: x += “ world” and x.concat “ world” Well, the += operator re-initializes the variable with a new value, so a += b is equivalent to a = a + b. Therefore, while it may seem that += is mutating the value, it’s actually creating a new object and pointing the the old variable to that new object. This is perhaps easier to understand if written as follows:

Consider: def foo(x) puts x * 2 end puts foo 5 # → 10 puts foo(5) # → 10 puts foo (5) # → 10 Now consider: def bar(y, z) puts y + z end puts bar 1, 2 # → 10 puts bar(1, 2) # → 10 puts bar (1, 2)…

What is the difference between calling super and calling super()? A call to super invokes the parent method with the same arguments that were passed to the child method. An error will therefore occur if the arguments passed to the child method Also, a call to super doesn’t match what the parent is expecting. But a call to super() invokes the parent method without any arguments, as presumably expected. As always, being explicit in your code is a good thing.

In Ruby code, you quite often see the trick of using an expression like: array.map(&:to_s) as a shorthand form of: array.map { |element| element.to_s } But, how exactly does it work? When a parameter is passed with & in front of it (indicating that is it to be used as a block), Ruby will call to_proc on it in an attempt to make it usable as a block. Symbol#to_proc quite handily returns a Proc that will invoke the method of the corresponding name on whatever is passed to it, thus enabling our little shorthand trick to work.

In ruby, the operators “&&” and “||” in ruby statements (not if-stmts) have some special properties. Let’s see how: stmt1 && stmt2 returns the first falsey result, or if no falsey’s found, returns the last truthy result example: ‘hello’ && ‘bye’ # => ‘bye’ ‘hello’ && false # => false …

Warning: The following post is my personal opinion. If you feel I’m wrong or you disagree with me, please reply to this post and I’ll will be so glad to read your opinions. Imagine with me for a second. One shiny morning, while working on your amazing project, written in…