scala programming tutorial

About ScalaScala is a "stretched language", which can be changed and grown with the needs of the user. Scala can be used in a wide range of programming tasks, as small as scripts to build systems. Scala runs on the standard Java platform and can interact seamlessly with all Java libraries. It adds object-oriented and functional

inside the OP, found the Addsap method, and the parameters were identical, so Scala would call this ADDSAP for processing, get the result 3, and the second print function would be similar.Output Result:3Hi ScalaFind four methods or paths for implicit conversions :First from the associated object of the current class,Second, the implicit object and the implicit value are placed in an object, and then imported into it, will be found in thisThird, the i

). It also includes an easy-to-use REPL for interactive development and analysis, just as with Python and R.I personally love Scala because it includes many practical programming features, such as pattern matching, and is considered much simpler than standard Java. However, using Scala to develop more than one method, this language as a feature to promote. It's a

immutability and functional programming to make my efficiency a big boost. Based on the dynamic nature of Lisp, I can always shape clojure into a state that fits the best abstraction. There would be no difference if there were no clojure,storm, but the process would be much more painful. "The next generation of distributed computing systems spark not only chooses Scala in its implementation, it also provid

would for other programs.This works because the trait application declares the main method with the appropriate signature and inherits it from the singleton object so that it can be used as a Scala program. The code between the braces is collected into the primary constructorof the Singleton object:Primary constructor, which is executed when the class is initialized.Inheriting from application is shorter than writing an explicit main method, but it a

Once an object is created, it will no longer change its contents, so that the object is immutable. This can be done without worrying about competition management when accessing objects in multiple threads, and Java's string is an example of an immutable object. Based on this, when you use Scala to create multithreaded applications, you can write unlocked code with the invariant state (immutable states) to write concise multithreaded code without worry

introduction of VaR and the generation of side effects. Remove VaR and only introduce the necessary Val. Instead of providing the required information to the caller of the method. A notable feature of functional programming is that there are many methods, but method functions are very specific. Here is an example: Print a multiplication table from 1 to 10. The Java method is a dual for loop. Scala is also

Mainly from the Coursera course "functional programming Principles in Scala"by Professor Martin Odersky, the inventor of the Scala language. 3. Data and Abstraction3.1 Class hierarchiesThis set of subtitles is out -,- of sync, listening to a little effort!The concept of a class is similar to that of other languages, such as base class, subclass, and p

Guide to Statistics network This paper introduces Scala's language characteristics from seven aspects, such as installation, basic data type, operator, function and so on. Not just a Python programmer, anyone with programming experience or a desire to get started can look at it and make a basic understanding of Scala. With the needs of business and data, we have introduced spark. Spark's support for Python

To create a string: The most straightforward way to create a string is to write a method that: var greeting = "Hello world!"; Or var greeting:string = "Hello world!"; Whenever you encounter a string in code, the compiler creates a string object and its value in this example using: "Hello world!", but if you like, you can give the string, because here I have alternately shown in the declaration. Object Test { Val greeting:string = "Hello, world!" def main (args:array[string]) { printl

method. Here's a standard way to invoke a method: functionname (List of parameters) If a function is invoked by an instance of an object, the following Java dot notation is used: [Instance.] functionname (List of parameters) Here is an example to define, and then call a function: Object Test { def main (args:array[string]) { println ("Returned Value:" + addint (5,7)); } def addint (A:int, b:int): Int = { var sum:int = 0 sum = a + b return sum } } Let's compile and run the above pr

Since it is functional programming, it is naturally unavoidable to know more about the function:Methods are not equal to functions (function)The method is not a function but can be converted into a function, can be converted by hand or automatically converted by the compiler (compiler) in appropriate cases. A reverse conversion is not a function that cannot be converted to a method. Let's take a look at the following example:1

Scala Programming implicit conversion and implicit parameter introduction Scala offers an implicit conversion and implicit parameter functionality that is very feature-specific. is a feature that is not in programming languages such as Java. It allows you to manually specify that an object of some type be converted to

was successful. This is followed by some basic grammar learning in Scala. val Variable declaration: declares a Val variable to hold the expression's computed result, which is immutable.Val result = 1 + 1 Subsequent constants are available for continuation, Eg:2 * result However, the Val constant declaration does not change its value, otherwise it returns an error. var variable declaration: DECLARE var variable, can change the refere

) Scala defaults to a direct delimiter for the behavior Code, X + y will be considered as two lines of code, x and + Y. But what if the same line of code needs to be wrapped. You can enclose the same sentence with parentheses, and you can use line breaks in parentheses. (x + y) is actually the line-break form of x + Y. Iii. Single-instance objects Although Scala is a functional

Introduction OK. The time has passed for another week. The first week has a May Day holiday, so I feel that the time is more than enough. In the middle of this week, no holiday can only be digested by evening and weekend time. In fact, it is still a little nervous! Later, we found that the video of each course also had corresponding courseware (Slide) and subtitles (subtitles) that could be downloaded. In this way, the download of video learning and online learning is only inferior to the Exerci

actor{var counter = 0Def Act () {while (true) {Receive {Case content:string = println ("Message:" + content)Case Hello (name, content,sender) + = {println ("Helloactor:" + "Name:" + name + "Content:" + content + counter)Counter + = 1Thread.Sleep (3000)Sender! Helloback (name, Content+counter, this)}}}}}Class Hellobackactor (Val helloactor:actor) extends actor{var counter = 0Def Act () {Helloactor! Hello ("Spark", "Love Was Here", this)while (true) {Receive {Case content:string = println ("Messa

independent of the data type. This nature is called the independence of the expression. In a large-scale development system, the expression of independence is very important. It allows you to change the implementation of a component without affecting the customer code9. Regular expressionsOne particularly useful application area of extractors is regular expressions.Like Java, Scala provides regular expressions through a library, but extractorsMake it

Today I studied Liaoliang's Scala learning lecture 70th, about Scala's interface programming, so let's take a preliminary look at the process of programming in Scala.Information from DT Big Data Dream Factory public account: Dt_sparkFollow the account to learn more about the Liaoliang Teacher's course contentTeacher Wang qq:1740415547No.: 18610086859First of all,

Today I studied Liaoliang's Scala learning lecture 70th, about Scala's interface programming, so let's take a preliminary look at the process of programming in Scala.Information from DT Big Data Dream Factory public account: Dt_sparkFollow the account to learn more about the Liaoliang Teacher's course contentTeacher Wang qq:1740415547No.: 18610086859First of all,