Ruby Programming Language Interview Preparation Guide

Ruby code blocks form an important part of ruby and are very fun to use. With the help of this feature you can place your code between do-end and you can associate them with method invocations and you can get an impression that they are like parameters. They may appear near to a source of the code and adjacent to a method call. The code is not executed during the program execution but it is executed when the context of its appearance is met or when it enters a method.

Interpolation is a very important process in Ruby. Interpolation is the process of inserting a string into a literal. There is only one way in which you can interpolate a string into a literal by placing a Hash (#) within {} open and close brackets. This refers to a new name to by referring to the copy of the original method.

Float class is used whenever the function changes constantly. It acts as a sub class of numeric. They represent real characters by making use of the native architecture of the double precision floating point.
Max is used whenever there is a huge need of Float.
Dig is used whenever you want to represent a float in decimal digits.

Unlike other programming languages ruby deals with extremely large numbers it doesn’t have any barriers. There is no limit on the extent of limit of number usage. Ruby performs this function with two different classes they are fixnum and bignum. Fixnum represents easily managed small numbers and bignum represents big numbers. Ruby entirely handles the functioning of these two classes which leaves a programmer to concentrate on his arithmetic operations.

A class variable starts with an @@ sign which is immediately followed by upper or lower case letter. You can also put some name characters after the letters which stand to be a pure optional. A class variable can be shared among all the objects of a class. A single copy of a class variable exists for each and every given class.
To write a global variable you start the variable with a $ sign which should be followed by a name character. Ruby defines a number of global variables which also include other punctuation characters such as $_ and $-k.

There are four different types of variables they are local, instance, global, and class. Variables can be used in the program without any declaration and they can contain data of any type. A local variable contains lower case characters followed by name characters. Instance variable starts with a @ sign followed by name characters.

Classes, variables, methods, constants and modules can be referred by ruby names. When you want to distinguish between various names you can specify that by the first character of the name. Some of the names are used as reserve words which should not be used for any other purpose. A name can be lowercase letter, upper case letter, number, or an underscore, make sure that you follow the name by name characters.

This function calls a method and it can take any number of arguments and expr. Make sure that you put an asterisk or an ampersand before the expression. Last expr argument can be declared with a hash without any braces. If you want to increase the size of the array value then make sure that you put an asterisk before expression. “::” can be used to separate the class from methods.

Methods in ruby basically perform two functions, named operation and the code present in the class which does a specific function. In Ruby all your algorithms live in methods which inturn is present on objects. Ruby does not have any provision for functions. Code present in Ruby is always a method of some object. Behind the scenes ruby gives you the flexibility to work with methods as functions if you are considering working with other languages.

Define operator defines whether a passed expression is defined or not. If the expression is defined it returns the description string or null if the expression is not defined. If a variable is defined it gets initialized. If method_call is defined as true then method also gets defined. This is also the same case with super and yield.