This tutorial explains the basics of Scala in a simple and reader-friendly way. Scala is more object-oriented than Java because in Scala, we cannot have static members. For example, matrices and tables are examples of structures that can be realized as two-dimensional arrays. A function definition can appear anywhere in a source file and Scala permits nested function definitions, that is, function definitions inside other function definitions. You should see the following −, Scala code runner version 2.11.5 -- Copyright 2002-2013, LAMP/EPFL, Scala code runner version 2.9.0.1 – Copyright 2002-2013, LAMP/EPFL. [0 /XYZ 34.5000000 >>

At the time of writing this tutorial, I downloaded ‘scala-2.11.5-installer.jar’. the variable reference and following format specifier should match otherwise it is showing error. Here, z is declared as an array of Strings that may hold up to three elements.

String substring(int beginIndex, int endIndex). Members of packages, classes or objects can be labeled with the access modifiers private and protected, and if we are not using either of these two keywords, then access will be assumed as public. A pattern match includes a sequence of alternatives, each starting with the keyword case. So here the Point class is called superclass and the class Location is called subclass. Any arbitrary expression can be embedded in ‘${}’. As shown above, you would have to import Array._ package before using any of the mentioned methods. /Subtype /Link The apply method has the same meaning as always: it turns Test into an object that can be applied to arguments in parentheses in the same way a method is applied. Throwing an exception looks the same as in Java. A private member is visible only inside the class or object that contains the member definition. Method parameters are always immutable which are defined by val keyword. Equivalent to [\t\n\r\f]. No external context is required. Returns an array containing repeated applications of a function to a start value. Following is the example code snippet to explain public member −. The purpose of that unapply method is to match a value and take it apart. The following is an example program to writing to a file. It is called Logical OR Operator.

The 'scala' command is similar to the java command, in that it executes your compiled Scala code. Method parameters are variables, which are used to pass the value inside a method, when the method is called. Variable friends will be accessible to any class within the enclosing package society. The syntax of an ‘if’ statement is as follows. is itself returned. x��]M��F�����c�

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Here it is required to know two important method of Scala, which are used in the following example. The trait Equal contain one implemented method that is isEqual() so when user defined class Point extends the trait Equal, implementation to isEqual() method in Point class should be provided. Scala's List[T] is a linked list of type T. A set is a collection of pairwise different elements of the same type. An 'if' can have zero to many else if's and they must come before the else. Scala implicitly converts the String to a RichString and invokes that method to get an instance of Regex. Concatenates the specified string to the end of this string. The collections may have an arbitrary number of elements or be bounded to zero or one element (e.g., Option). 14 0 obj This chapter takes you through how to use classes and objects in Scala programming. [0 /XYZ 34.5000000 Whether you are an experienced programmer or not, this website is intended for everyone who wishes to learn the Scala programming language. Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array. Scala allows you to express general programming patterns in an effective way. The Scala compiler compiles your Scala code into Java Byte Code, which can then be executed by the 'scala' command. We create a String and call the r( ) method on it. Then the file should be saved as 'HelloWorld.scala'. static String valueOf(primitive data type x). In the above code, we have created an object ScalaExample. A value class not allowed to extend traits. Try the following code −.

Classes are extended by subclassing and a flexible mixin-based composition mechanism as a clean replacement for multiple inheritance. In other words, a function, which is defined as a member of some object, is called a method. End of entire string except allowable final line terminator. ), does not expect you to provide redundant type information. Closure − A closure is a function, whose return value depends on the value of one or more variables declared outside this function.

Returns a two-dimensional array containing values of a given function over ranges of integer values starting from 0. If you want to use the different methods then it is required to import Array._ package. Matches exactly n number of occurrences of preceding expression. /Contents 18 0 R A character literal is a single character enclosed in quotes. Scala functions are the heart of Scala programming and that's why Scala is assumed as a functional programming language. A keyword cannot be used as an identifier and identifiers are case-sensitive. To use ScalaMock in sbt with ScalaTestadd the following to your build.sbt. [/Pattern /DeviceRGB] This section explains all basic Scala Literals.
Returns an array containing equally spaced values in some integer interval. As mentioned earlier in this chapter, you can create objects using a keyword new and then you can access class fields and methods as shown below in the example −. Tests if this string starts with the specified prefix beginning a specified index. Therefore, by assigning different data types to variables, you can store integers, decimals, or characters in these variables. >> You can wrap an expression with a finally clause if you want to cause some code to execute no matter how the expression terminates. For example, let us assume variable A holds 10 and variable B holds 20, then −, The following relational operators are supported by Scala language. If the behavior will not be reused, then make it a concrete class. It is not reusable behavior after all.
Scala also allows traits to be partially implemented but traits may not have constructor parameters. A singleton is a class that can have only one instance, i.e., Object.

endobj Instances x of this trait allow method invocations x.meth(args) for arbitrary method names meth and argument lists args as well as field accesses x.field for arbitrary field namesfield. It will create a file named Demo.txt in the current directory, where the program is placed. It contains a primary constructor with exactly one val parameter.