What does @variable mean in Ruby?
In Ruby, the at-sign ( @ ) before a variable name (e.g. @variable_name ) is used to create a class instance variable. These variables are: … Specific to each instantiated object of the class they’re defined in (i.e. each class object instance has a separate copy of these variables).
What is all in Ruby?
The all?() of enumerable is an inbuilt method in Ruby returns a boolean value true if all the objects in the enumerable satisfies the given condition, else it returns false. If a pattern is given, it compares with the pattern, and returns true if all of them are equal to the given pattern, else it returns false.
What does .NEW mean in Ruby?
The important bit to learn for you is: the method initialize is a special method with a special meaning in Ruby: Whenever you call the method new on a class, as in Person. new , the class will create a new instance of itself. It will then, internally, call the method initialize on the new object.
What does || mean in Ruby?
||= is called a conditional assignment operator. It basically works as = but with the exception that if a variable has already been assigned it will do nothing. First example: x ||= 10. Second example: x = 20 x ||= 10. In the first example x is now equal to 10.
What is Colon in Ruby?
Ruby symbols are created by placing a colon (:) before a word. You can think of it as an immutable string. A symbol is an instance of Symbol class, and for any given name of symbol there is only one Symbol object.
What does .freeze do in Ruby?
The freeze method in Ruby is used to ensure that an object cannot be modified. This method is a great way to create immutable objects. Any attempt to modify an object that has called the freeze method will result in the program throwing a runtime error.
What is enumerator in Ruby?
Enumerator, specifically, is a class in Ruby that allows both types of iterations – external and internal. Internal iteration refers to the form of iteration which is controlled by the class in question, while external iteration means that the environment or the client controls the way iteration is performed.
How do you use substring in Ruby?
There is no substring method in Ruby. Instead we rely upon ranges and expressions. Substring ranges. With a range, we use periods in between 2 numbers—the first and last index of the substring.
What does enumerable mean in Ruby?
Enumeration refers to traversing over objects. In Ruby, we call an object enumerable when it describes a set of items and a method to loop over each of them.
What is class self in Ruby?
Every object in Ruby has and is aware of its self. The keyword self in Ruby enables you to access to the current object — the object that is receiving the current message. … Using self inside an instance or class method refers to the same object the method is being called on, i.e., and instance and class respectively.
How do you say hi in Ruby?
Instructions. You will build a method called say_hello . This method should accept the argument of a person’s name. It then should print “Hello ” with the name followed by an exclamation point (don’t forget that space after the “Hello”).
Are multiple Initializers allowed in Ruby?
You can indeed have two constructors.
What is unless in Ruby?
Ruby provides a special statement which is referred as unless statement. This statement is executed when the given condition is false. … In if statement, the block executes once the given condition is true, however in unless statement, the block of code executes once the given condition is false.
What is double pipe in Ruby?
My own definition is that “double-pipe equals” is an operator that assigns a value, much like = or our classic assignment operator, but will only complete the assignment if the left side of our operation returns false or nil . …
Which is better Python or Ruby?
Python is faster than Ruby, but they’re both in a category of interpreted languages. Your fastest language is always going to be one that’s compiled down to byte code or object code right on the computer. Both Ruby and Python exist a level above that, they’re abstracted.