What is the question mark in Ruby?
It’s a convention in Ruby that methods that return boolean values end in a question mark. There’s no more significance to it than that. In your example it’s just part of the method name. In Ruby you can also use exclamation points in method names!
What does exclamation mark in Ruby mean?
Bang or exclamation mark means that you are making a permanent saved change in your code. If you use for example Ruby’s method for global substitution gsub! the substitution you make is permanent.
What is return in Ruby?
Explicit return Ruby provides a keyword that allows the developer to explicitly stop the execution flow of a method and return a specific value. The return keyword returns nil if no value is passed as argument.
What is predicate in Ruby?
A method that returns true or false is called a “predicate method”. In Ruby, there is a naming convention where predicate methods end with a question mark. For instance, if you have an Invoice class and are writing an instance method that returns whether the invoice has been paid or not, you would name the method paid?
What do the question mark and exclamation mark mean in Ruby?
They are conventions in the Ruby community. A question mark method, also known as a predicate method, is supposed to return either true or false An exclamation mark method says that it will do something different than the non-exclamation mark version.
What is the difference between question mark and exclamation mark methods?
1 A question mark method, also known as a predicate method, is supposed to return either true or false 2 An exclamation mark method says that it will do something different than the non-exclamation mark version. 3 The equals sign method means assignment. It’s used to assign a value to an instance variable
What does it mean when a ruby method ends in?
In general, methods that end in ! indicate that the method will modify the object it’s called on. Ruby calls these as ” dangerous methods ” because they change state that someone else might have a reference to. Here’s a simple example for strings:
Why do all methods return a value in Ruby?
One key concept in Ruby is that ALL methods return a value. Let me explain! As a result of calling a method, you get something back. This “something” that you get comes from the last expression in your method definition. We call this “implicit return”, just a fancy name for “automatically return the last thing”.