yazik.info Tutorials Scala Tutorial Pdf


Friday, May 31, 2019

Scala Programming is based on Java, so if you are aware of Java syntax, then yazik.info or this tutorial may not be redistributed or reproduced in any. tutorial explains the basics of Scala in a simple and reader-friendly way. Scala Programming is based on Java, so if you are aware of Java syntax, then it's. Scala Tutorial in PDF - Learn Scala in simple and easy steps starting from basic to advanced concepts with examples including Scala Syntax Object Oriented.

Scala Tutorial Pdf

Language:English, Spanish, German
Published (Last):25.01.2016
ePub File Size:15.83 MB
PDF File Size:12.86 MB
Distribution:Free* [*Register to download]
Uploaded by: NILA

At the same time, Scala is compatible with Java. Java libraries and frameworks can be used without glue code or additional declarations. A Scala Tutorial for Java programmers. Version January 16, Michel Schinz, Philipp. Haller. PROGRAMMING METHODS LABORATORY. EPFL. tutorial. For a more precise reference, the reader is referred to the Scala Language Specification [35]. There are also several tutorials on Scala available [ 34, 18].

A detailed description of this program is given in next chapters. In Scala, you can create any type of application in less time and coding whether it is web based, mobile based or desktop based application.

Scala provides you powerful tools and API by using which you can create applications. Here, You can use play framework which provides a platform to build web application rapidly.

We assure that you will not find any problem in this Scala tutorial. But if there is any mistake, please post the problem in contact form.

JavaTpoint offers too many high quality services. Mail us on hr javatpoint. Please mail your requirement at hr javatpoint. Scala Tutorial. Scala Functions Higher Order Functions.

Scala Tutorial in PDF

Scala Trait Scala Trait Mixins. Scala Access Modifiers. Scala Array Multidimensional Array. Scala Tuples Scala Tuple Example. Next Topic History of Scala. Verbal A. Compiler D. Web Tech.

Cyber Sec. Control S. Javatpoint Services JavaTpoint offers too many high quality services. Multiple classes can be imported from the same package by enclosing them in curly braces as on the first line. The import statement on the third line therefore imports all members of the DateFormat class.

Next, we define a date format using the static getDateInstance method that we imported previously. Finally, we print the current date formatted according to the localized DateFormat instance.

Methods taking one argument can be used with an infix syntax. That is, the expression df format now is just another, slightly less verbose way of writing the expression df. To conclude this section about integration with Java, it should be noted that it is also possible to inherit from Java classes and implement Java interfaces directly in Scala.

It differs from Java in that respect, since Java dis- tinguishes primitive types such as boolean and int from reference types, and does not enable one to manipulate functions as values.

Therefore, it would break the fol- lowing expression: 1. The reason that this tokenization is chosen is because 1.

The token 1. Writing the expression as: 1. It is therefore possible to pass functions as arguments, to store them in variables, and to return them from other functions. This ability to manipulate functions as values is one of the cornerstone of a very interesting programming paradigm called functional programming.

Want to learn Apache Spark with Scala? Looking for a place to begin?

How do we pass it the action to perform? Quite logically, as a function.

This very simple kind of function passing should be familiar to many programmers: it is often used in user-interface code, to register call-back functions which get called when some event occurs.

In the following program, the timer function is called oncePerSecond, and it gets a call-back function as argument.

The main function of this program simply calls this timer function with a call-back which prints a sentence on the terminal. First of all, no- tice that the function timeFlies is only defined in order to be passed later to the oncePerSecond function. Having to name that function, which is only used once, might seem unnecessary, and it would in fact be nice to be able to construct this function just as it is passed to oncePerSecond. This is possible in Scala using anony- mous functions, which are exactly that: functions without a name.

In this example, the argument list is empty, as witnessed by the empty pair of parenthesis on the left of the arrow. The body of the function is the same as the one of timeFlies above. One important difference is that classes in Scala can have parameters. This is illustrated in the following definition of complex numbers.


These arguments must be passed when creating an instance of class Complex, as follows: new Complex 1. The class contains two meth- ods, called re and im, which give access to these two parts. It should be noted that the return type of these two methods is not given explicitly. It will be inferred automatically by the compiler, which looks at the right-hand side of these methods and deduces that both return a value of type Double.

The compiler is not always able to infer types like it does here, and there is unfortu- nately no simple rule to know exactly when it will be, and when not.

In practice, this is usually not a problem since the compiler complains when it is not able to infer a type which was not given explicitly. As a simple rule, beginner Scala programmers should try to omit type declarations which seem to be easy to deduce from the con- text, and see if the compiler agrees. After some time, the programmer should get a good feeling about when to omit types, and when to specify them explicitly. This is perfectly doable in Scala, simply by defining them as methods without arguments.

When no super-class is specified, as in the Complex example of previous section, scala.

AnyRef is implicitly used. It is possible to override methods inherited from a super-class in Scala. It is how- ever mandatory to explicitly specify that a method overrides another one using the override modifier, in order to avoid accidental overriding. As an example, our Complex class can be augmented with a redefinition of the toString method inher- ited from Object. For example, in- terpreters and compilers usually represent programs internally as trees; XML doc- uments are trees; and several kinds of containers are based on trees, like red-black trees.

We will now examine how such trees are represented and manipulated in Scala through a small calculator program. The aim of this program is to manipulate very simple arithmetic expressions composed of sums, integer constants and variables.

We first have to decide on a representation for such expressions. The most natural one is the tree, where nodes are operations here, the addition and leaves are values here constants or variables.

Scala Tutorial

In Java, such a tree would be represented using an abstract super-class for the trees, and one concrete sub-class per node or leaf. In a functional programming language, one would use an algebraic data-type for the same purpose.

Scala provides the con- cept of case classes which is somewhat in between the two. Now that we have defined the data-type to represent our arithmetic expressions, we can start defining operations to manipulate them.

We will start with a function to evaluate an expression in some environment. The aim of the environment is to give values to variables.

Follow by Email

We therefore have to find a way to represent environments. We could of course use some associative data-structure like a hash table, but we can also directly use functions! An environment is really nothing more than a function which associates a value to a variable name. Before writing the evaluation function, let us give a name to the type of the environ- ments. We can now give the definition of the evaluation function.

Conceptually, it is very simple: the value of a sum of two expressions is simply the sum of the value of these expressions; the value of a variable is obtained directly from the environment; and the value of a constant is the constant itself.

Intu- itively, the meaning of the above definition should be clear: 1. We see that the basic idea of pattern matching is to attempt to match a value to a series of patterns, and as soon as a pattern matches, extract and name various parts of the value, to finally evaluate some code which typically makes use of these named parts.

A seasoned object-oriented programmer might wonder why we did not define eval as a method of class Tree and its subclasses.What is less familiar to Java programmers is the object declaration containing the main method.

It also assumed a basic knowledge of object-oriented programming, especially in Java. It was designed by Martin Odersky. Report Attrition rate dips in corporate India: Sign up. Net support in Scala is an object-oriented and functional programming language.