Ruby Basic Syntax Last Updated : 06 Sep, 2019 Comments Improve Suggest changes Like Article Like Report Ruby is a pure Object-Oriented language developed by Yukihiro Matsumoto (also known as Matz in the Ruby community) in the mid 1990’s in Japan. To program in Ruby is easy to learn because of its similar syntax to already widely used languages. Here, we will learn the basic syntax of Ruby language. Let us write a simple program to print "Hello World!". Ruby # this line will print "Hello World!" as output. puts "Hello World!"; Output: Hello World! End of a line in Ruby Ruby interprets newline characters(\n) and semicolons(;) as the end of a statement. Note: If a line has +, - or backslash at the end of a line, then it indicates the continuation of a statement. Whitespace in Ruby Whitespace characters such as spaces and tabs are generally ignored in Ruby code, except when they appear in a string, i.e. it ignores all spaces in a statement But sometimes, whitespaces are used to interpret ambiguous statements. Example : a / b interprets as a/b (Here a is a variable) a b interprets as a(b) (Here a is a method) Ruby # declaring a function named 'a' which accepts an # integer and return 1 def a(u) return 1 end # driver code a = 3 b = 2 # this a + b interprets as a + b, so prints 5 as output puts(a + b) # this a b interprets as a(b) thus the returned # value is printed puts(a b) Output: 5 1 Ruby BEGIN and END statement BEGIN statement is used to declare a part of code which must be called before the program runs. Syntax: BEGIN { # code written here } Similarly, END is used to declare a part of code which must be called at the end of program. Syntax: END { # code written here } Example of BEGIN and END Ruby # Ruby program of BEGIN and END puts "This is main body of program" END { puts "END of the program" } BEGIN { puts "BEGINNING of the Program" } Output: BEGINNING of the Program This is main body of program Ruby comments A comment hides some part of code, from the Ruby Interpreter. Comments can be written in different ways, using hash character(#) at the beginning of a line. Syntax : #This is a single line comment #This is multiple #lines of comment =begin This is another way of writing comments in a block fashion =end Identifiers in Ruby Identifiers are names of variables, constants and functions/methods. Ruby identifiers are case sensitive. Ruby identifiers may consists of alphanumeric characters and also underscore ( _ ). For example: Man_1, item_01 are examples of identifiers. Keywords in Ruby The reserved words in Ruby which cannot be used as constant or variable names are called keywords of Ruby. BEGIN do next then END else nil true alias elsif not undef and end or unless begin ensure redo until case for retry while break false rescue when def in self __FILE__ class if return while Comment More infoAdvertise with us Next Article Hello World in Ruby M ManishKhetan Follow Improve Article Tags : Ruby Ruby-Basics Similar Reads Ruby Programming Language Ruby is a dynamic, reflective, object-oriented, general-purpose programming language. Ruby is a pure Object-Oriented language developed by Yukihiro Matsumoto. Everything in Ruby is an object except the blocks but there are replacements too for it i.e procs and lambda. The objective of Ruby’s develop 2 min read OverviewRuby For BeginnersRuby is a dynamic, reflective, object-oriented, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan. This article will cover its basic syntax and some basic programs. This article is divided into various sections for various topi 3 min read Ruby Programming Language (Introduction)Ruby is a pure Object-Oriented language developed by Yukihiro Matsumoto (also known as Matz in the Ruby community) in the mid 1990’s in Japan. Everything in Ruby is an object except the blocks but there are replacements too for it i.e procs and lambda. The objective of Ruby's development was to make 4 min read Comparison of Java with Other Programming LanguagesJava is one of the most popular and widely used programming languages and platforms. A platform is an environment that helps to develop and run programs written in any programming language. Java is fast, reliable, and secure. From desktop to web applications, scientific supercomputers to gaming cons 4 min read Similarities and Differences between Ruby and C languageSimilarities between Ruby and C There are many similarities between C and Ruby, and some of them are: Like C, in Ruby also… A programmer is able to program procedurally if they like to do. But still, behind the scenes, it will be object-oriented.Both the languages have the same operators, for exampl 3 min read Similarities and Differences between Ruby and C++There are many similarities between C++ and Ruby, some of them are: Just like C++, in Ruby… As in C++, public, private, and protected works similarly in Ruby also .Inheritance syntax is still only one character, but it’s < instead of : in Ruby.The way ‘namespace’ is used in C++, in the similar wa 3 min read Environment Setup in RubyRuby is an interpreted, high-level, general-purpose programming language. Ruby is dynamically typed and uses garbage collection. It supports multiple programming paradigms, object-oriented, including procedural and functional programming. Ruby is based on many other languages like Perl, Lisp, Smallt 3 min read How to install Ruby on Linux?Prerequisite: Ruby Programming Language Before we start with the installation of Ruby on Linux, we must have first-hand knowledge of what Ruby is?. Ruby is a pure Object-Oriented language developed by Yukihiro Matsumoto (also known as Matz in the Ruby community) in the mid-1990s in Japan. Everything 2 min read How to install Ruby on Windows?Prerequisite: Ruby Programming Language Before we start with the installation of Ruby on Windows, we must have first-hand knowledge of what Ruby is?. Ruby is a pure Object-Oriented language developed by Yukihiro Matsumoto (also known as Matz in the Ruby community) in the mid-1990s in Japan. Everythi 2 min read Interesting facts about Ruby Programming LanguageRuby is an interpreted, high-level, dynamic, general-purpose, open source programming language which focuses on simplicity and productivity. It was designed and developed in the mid-1990s by Yukihiro Matsumoto (also known as Matz in the Ruby community) in Japan. Here are some interesting facts about 2 min read BasicsRuby | KeywordsKeywords or Reserved words are the words in a language that are used for some internal process or represent some predefined actions. These words are therefore not allowed to use as variable names or objects or as constants. Doing this may result in compile-time error. Example: Ruby # Ruby program to 4 min read Ruby | Data TypesData types in Ruby represents different types of data like text, string, numbers, etc. All data types are based on classes because it is a pure Object-Oriented language. There are different data types in Ruby as follows: NumbersBooleanStringsHashesArraysSymbols Numbers: Generally a number is defined 3 min read Ruby Basic SyntaxRuby is a pure Object-Oriented language developed by Yukihiro Matsumoto (also known as Matz in the Ruby community) in the mid 1990’s in Japan. To program in Ruby is easy to learn because of its similar syntax to already widely used languages. Here, we will learn the basic syntax of Ruby language. Le 3 min read Hello World in RubyRuby is a dynamic, reflective, object-oriented, general-purpose programming language. Hello World the program is the most basic and first program when we start a new programming language. This simply prints Hello World on the screen. Below is the program to write hello world". How to run a Ruby Prog 2 min read Ruby | Types of VariablesThere are different types of variables in Ruby: Local variables Instance variables Class variables Global variables Each variable in Ruby is declared by using a special character at the start of the variable name which is mentioned in the following table: Symbol Type of Variable [a-z] or _ Local Var 4 min read Global Variable in RubyGlobal Variable has global scope and accessible from anywhere in the program. Assigning to global variables from any point in the program has global implications. Global variable are always prefixed with a dollar sign ($). If we want to have a single variable, which is available across classes, we n 2 min read Comments in RubyStatements that are not executed by the compiler and interpreter are called Comments. During coding proper use of comments makes maintenance easier and finding bugs easily.In Ruby, there are two types of comments:  Single – line comments.Multi – line comments. Here, we are going to explain both typ 2 min read Ruby | RangesPrerequisite: Ruby Range Operator Ruby ranges depict a set of values with a beginning and an end. Values of a range can be numbers, characters, strings or objects. It is constructed using start_point..end_point, start_point...endpoint literals, or with ::new. It provides the flexibility to the code 4 min read Ruby LiteralsAny constant value which can be assigned to the variable is called as literal/constant. we use literal every time when typing an object in the ruby code. Ruby Literals are same as other programming languages, just a few adjustments, and differences here. These are following literals in Ruby. Boolean 4 min read Ruby DirectoriesA directory is a location where files can be stored. For Ruby, the Dir class and the FileUtils module manages directories and the File class handles the files. Double dot (..) refers to the parent directory for directories and single dot(.)refers to the directory itself.The Dir Class The Dir class p 5 min read Ruby | OperatorsAn operator is a symbol that represents an operation to be performed with one or more operand. Operators are the foundation of any programming language. Operators allow us to perform different kinds of operations on operands. There are different types of operators used in Ruby as follows: Arithmetic 11 min read Operator Precedence in RubyOperators are used to perform different kinds of operations on operands. Which operator is performed first in an expression with more than one operators with different precedence is determined by operator precedence. when two operators of the same precedence appear in expression associativity is use 2 min read Operator Overloading in RubyRuby permits operator overloading, allowing one to define how an operator shall be used in a particular program. For example a '+' operator can be define in such a way to perform subtraction instead addition and vice versa. The operators that can be overloaded are +, -, /, *, **, %, etc and some ope 5 min read Ruby | Pre-define Variables & ConstantsRuby Predefine Variables Ruby contains a wide range of predefined variables. Every predefined variable has its own specification. You can use predefine variables to perform a specific task like when dealing with interpreter parameters or regular expressions. The list of predefined variables in Ruby 5 min read Ruby | unless Statement and unless ModifierRuby provides a special statement which is referred as unless statement. This statement is executed when the given condition is false. It is opposite of if statement. In if statement, the block executes once the given condition is true, however in unless statement, the block of code executes once th 2 min read Control StatementsRuby | Decision Making (if, if-else, if-else-if, ternary) | Set - 1Decision Making in programming is similar to decision making in real life. In programming too, a certain block of code needs to be executed when some condition is fulfilled. A programming language uses control statements to control the flow of execution of the program based on certain conditions. Th 3 min read Ruby | Loops (for, while, do..while, until)Looping is a fundamental concept in programming that allows for the repeated execution of a block of code based on a condition. Ruby, being a flexible and dynamic language, provides various types of loops that can be used to handle condition-based iterations. These loops simplify tasks that require 5 min read Ruby | Case StatementThe case statement is a multiway branch statement just like a switch statement in other languages. It provides an easy way to forward execution to different parts of code based on the value of the expression. There are 3 important keywords which are used in the case statement: case: It is similar to 3 min read Ruby | Control Flow AlterationPrerequisite : Decision Making , Loops Ruby programming language provides some statements in addition to loops, conditionals, and iterators, which are used to change the flow of control in a program. In other words, these statements are a piece of code that executes one after another until the condi 7 min read Ruby Break and Next StatementIn Ruby, we use a break statement to break the execution of the loop in the program. It is mostly used in while loop, where value is printed till the condition, is true, then break statement terminates the loop. Syntax : Break Example : Ruby # Ruby program to use break statement #!/usr/bin/ruby -w i 2 min read Ruby redo and retry StatementIn Ruby, Redo statement is used to repeat the current iteration of the loop. redo always used inside the loop. The redo statement restarts the loop without evaluating the condition again. Ruby # Ruby program of using redo statement #!/usr/bin/ruby restart = false # Using for loop for x in 2..20 if x 2 min read BEGIN and END Blocks In RubyEvery Ruby source file can run as the BEGIN blocks when the file is being loaded and runs the END blocks after the program has finished executing. The BEGIN and END statements are different from each other. A program may contain multiple BEGIN and END blocks. If there is more than one BEGIN statemen 2 min read File Handling in RubyIt is a way of processing a file such as creating a new file, reading content in a file, writing content to a file, appending content to a file, renaming the file and deleting the file. Common modes for File Handling "r" : Read-only mode for a file. "r+" : Read-Write mode for a file. "w" : Write-onl 4 min read MethodsRuby | MethodsMethod is a collection of statements that perform some specific task and return the result. Methods are time savers and help the user to reuse the code without retyping the code. Defining & Calling the method: In Ruby, the method defines with the help of def keyword followed by method_name and e 3 min read Method Visibility in RubyMethod visibility in Ruby refers that instance methods can be public, private or protected. Methods are by default public unless they are explicitly declared private or protected. Method visibility is used in Ruby to achieve Data Abstraction i.e showing only required information and hiding the backg 3 min read Recursion in RubyThe process in which a function calls itself directly or indirectly is called recursion and the corresponding function is called a recursive function. Recursion makes the process easier and it reduces a lot of compiling time. In Ruby, we can put all the actions in a loop, so that they can be repeate 4 min read Ruby Hook MethodsRuby Hook Methods are called in reaction to something you do. They are usually used to extend the working of methods at run time. These methods are not defined by default, but a programmer can define them according to imply them on any object or class or module and they will come into picture when c 5 min read Ruby | Range Class MethodsPrerequisite: Ruby | Ranges Ruby provides a Range class. Ruby ranges depict a set of values with a beginning and an end. Values of a range can be numbers, characters, strings or objects. It is constructed using start_point..end_point, start_point…endpoint literals, or with ::new. It provides the fle 5 min read The Initialize Method in RubyThe initialize method is useful when we want to initialize some class variables at the time of object creation. The initialize method is part of the object-creation process in Ruby and it allows us to set the initial values for an object. Below are some points about Initialize : We can define defaul 2 min read Ruby | Method overridingMethod is a collection of statements that perform some specific task and return the result. Override means two methods having same name but doing different tasks. It means that one of the methods overrides another method. If there is any method in the superclass and a method with the same name in it 2 min read Ruby Date and TimeThe class Time and Date in Ruby deals with the dates and times. It helps us to get the current time and date according to our system configurations. It also gives us the components of a date and time and also to format time and date. The date is the day of a month or year that is represented by a nu 3 min read OOP ConceptsObject-Oriented Programming in Ruby | Set 1When we say object-oriented programming, we mean that our code is centered on objects. Objects are real-life instances that are classified into various types. Let’s take an example to understand this better. If we consider a rose as an object, then the class of the rose will be flower. A class is li 9 min read Object Oriented Programming in Ruby | Set-2Prerequisite: Object Oriented Programming in Ruby | Set-1 Inheritance Inheritance is one of the solid fundamental characteristics of object-oriented programming. sometimes we might need certain features of a class to be replicated into another class. Instead of creating that attribute again, we can 8 min read Ruby | Class & ObjectRuby is an ideal object-oriented programming language. The features of an object-oriented programming language include data encapsulation, polymorphism, inheritance, data abstraction, operator overloading etc. In object-oriented programming classes and objects plays an important role. A class is a b 4 min read Private Classes in RubyThe concept of private, protected and public methods in Ruby is a bit different than it other languages like Java. In Ruby, it is all about which class the person is calling, as classes are objects in ruby. Private Class When a constant is declared private in Ruby, it means this constant can never b 3 min read Freezing Objects | RubyAny object can be frozen by invoking Object#freeze. A frozen object can not be modified: we can't change its instance variables, we can't associate singleton methods with it, and, if it is a class or module, we can't add, delete, or modify its methods. To test if an object is frozen we can use Objec 2 min read Ruby | InheritanceRuby is the ideal object-oriented language. In an object-oriented programming language, inheritance is one of the most important features. Inheritance allows the programmer to inherit the characteristics of one class into another class. Ruby supports only single class inheritance, it does not suppor 4 min read Polymorphism in RubyIn Ruby, one does not have anything like the variable types as there is in other programming languages. Every variable is an "object" which can be individually modified. One can easily add methods and functions on every object. So here, the Object Oriented Programming plays a major role. There are m 3 min read Ruby | ConstructorsA constructor is a special method of the class that gets automatically invoked whenever an instance of the class is created. Like methods, a constructor may also contain a group of instructions or a method that will execute at the time of object creation. Important points to remember about Construct 2 min read Ruby | Access ControlAccess control is a very important part of the object-oriented programming language which is used to restrict the visibility of methods and member fields to protect data from the accidental modification. In terms of access control, Ruby is different from all other Object Oriented Programming languag 8 min read Ruby | EncapsulationEncapsulation is defined as the wrapping up of data under a single unit. It is the mechanism that binds together code and the data it manipulates. In a different way, encapsulation is a protective shield that prevents the data from being accessed by the code outside this shield. Technically in encap 2 min read Ruby MixinsBefore studying about Ruby Mixins, we should have the knowledge about Object Oriented Concepts. If we don't, go through Object Oriented Concepts in Ruby . When a class can inherit features from more than one parent class, the class is supposed to have multiple inheritance. But Ruby does not support 3 min read Instance Variables in RubyThere are four different types of variables in Ruby- Local variables, Instance variables, Class variables and Global variables. An instance variable in ruby has a name starting with @ symbol, and its content is restricted to whatever the object itself refers to. Two separate objects, even though the 3 min read Data Abstraction in RubyThe idea of representing significant details and hiding details of functionality is called data abstraction. The interface and the implementation are isolated by this programming technique. Data abstraction is one of the object oriented programming features as well. Abstraction is trying to minimize 3 min read Ruby Static MembersIn Programming, static keywords are primarily used for memory management. The static keyword is used to share the same method or variable of a class across the objects of that class. There are various members of a class in Ruby. Once an object is created in Ruby, the methods and variables for that o 3 min read ExceptionsRuby | ExceptionsA good program(or programmer) predict error and arrange to handle them in an effective manner. This is not as easy as it sounds. Exceptions are the errors that occur at runtime. It halts the execution of a program. They are caused by an extensive variety of exceptional circumstances, such as running 4 min read Ruby | Exception handlingIn Ruby, exception handling is a process which describes a way to handle the error raised in a program. Here, error means an unwanted or unexpected event, which occurs during the execution of a program, i.e. at run time, that disrupts the normal flow of the program's instructions. So these types of 6 min read Catch and Throw Exception In RubyAn exception is an object of class Exception or a child of that class. Exceptions occurs when the program reaches a state in its execution that's not defined. Now the program does not know what to do so it raises an exception. This can be done automatically by Ruby or manually. Catch and Throw is si 3 min read Raising Exceptions in RubyAn exception is an unwanted or unexpected event, which occurs during the execution of a program i.e at runtime, that disrupts the normal flow of the program’s instructions. As we know, the code enclosed between begin and end block is totally secured for handling Exceptions and the rescue block tells 4 min read Ruby | Exception Handling in Threads | Set - 1Threads can also contain exceptions. In Ruby threads, the only exception arose in the main thread is handled but if an exception arises in the thread(other than main thread) cause the termination of the thread. The arising of an exception in a thread other than the main thread depends upon abort_on_ 2 min read Ruby | Exception Class and its MethodsAn exception is an unwanted or unexpected event, which occurs during the execution of a program, i.e. at runtime, that disrupts the normal flow of the program’s instructions. In Ruby, descendants of an Exception class are used to interface between raise methods and rescue statements in the begin or 3 min read Ruby RegexRuby | Regular ExpressionsA regular expression is a sequence of characters that define a search pattern, mainly for use in pattern matching with strings. Ruby regular expressions i.e. Ruby regex for short, helps us to find particular patterns inside a string. Two uses of ruby regex are Validation and Parsing. Ruby regex can 3 min read Ruby Search and Replacesub and gsub string methods that use regular expressions, and their in-place variants are sub! and gsub!. The sub & sub! replaces the first occurrence of the pattern and gsub & gsub! replaces all occurrences. All of these methods perform a search-and-replace operation using a Regexp pattern. sub! an 2 min read Ruby ClassesRuby | Float ClassIn Ruby, Float class is a subclass of Numeric class. The objects of the Float class represents real numbers using the native architecture's double- precision floating-point representation. Public Instance Methods Arithmetic Operations: This method perform various arithmetic operations on float. Addi 7 min read Ruby | Integer ClassIn Ruby, Integer class is the basis for the two concrete classes that hold whole numbers. These concrete classes are Bignum and Fixnum. Fixnum holds integer values that are shown in the native machine word, whereas Bignum holds the integer value outside the range of Fixnum. Integer class contains a 3 min read Ruby | Symbol ClassThe objects of the Symbol class represent the names present inside the Ruby interpreter. They are usually generated by using :name literal syntax or by using to_sym methods. The similar Symbol objects are created for a given name string for the duration of a program's execution, regardless of the co 5 min read Ruby | Struct ClassStruct is a compact way to group together a number of attributes, using accessor methods, without creating an explicit class. The Struct class is a creator of specific classes, each one is defined to hold a set of variable and their accessors. The subclass of Struct class is Struct::Tms. Example: Ru 5 min read Ruby | Dir Class and its methodsA directory is a place for storing files. In Ruby, directories are handled by the Dir class and files are handled by the File class. In directories double dot(..) denotes parent directory and single dot(.) denotes directory itself. Class Methods 1. mkdir : This method is used to create a new directo 3 min read Ruby | MatchData ClassIn Ruby, all the pattern matching is done with the help of special variable $~. All the pattern matches will set the $~ to a MatchData that contains the information about the match. The MatchData objects are returned by the Regexp#match and Regexp.last_match methods. The MatchData objects enclosed a 4 min read Ruby ModuleRuby | ModuleA Module is a collection of methods, constants, and class variables. Modules are defined as a class, but with the module keyword not with class keyword. Important Points about Modules: You cannot inherit modules or you can't create a subclass of a module. Objects cannot be created from a module. Mod 4 min read Ruby | Comparable ModuleIn Ruby, the mixin of Comparable is used by the class whose objects may be ordered. The class must be defined using an operator which compare the receiver against another object. It will return -1, 0, and 1 depending upon the receiver. If the receiver is less than another object, then it returns -1, 3 min read Ruby | Math ModuleIn Ruby, Modules are defined as a collection of methods, classes, and constants together. Math module consists of the module methods for basic trigonometric and transcendental functions. Module ConstantsNameDescriptionEDefine the value of base of natural logarithm e.PIDefine the value of Ï€. Example: 4 min read Include v/s Extend in RubyInclude is used to importing module code. Ruby will throw an error when we try to access the methods of import module with the class directly because it gets imported as a subclass for the superclass. So, the only way is to access it through the instance of the class. Extend is also used to importin 2 min read Like