Programmer Think

Function definition and use The most common way to define a function is as a member of a class or object. This function is called a method, and its basic syntax is def Method name(parameter list):Result type={Method body} Literal quantity includes integer literal quantity, floating-point literal quantity, Boolean literal quantity, c ...

The first Scala program interactive programming hadoop@master:~/desktop/ScalaLearn$ scala Welcome to Scala 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_162). Type in expressions for evaluation. Or try :help. scala> 1+1 res0: Int = 2 scala> println("Hello World!") Hello World! scala> Script form gedit HelloWorld. ...

1, Spark overview 1.1 what is Spark Spark is a fast, universal and scalable big data analysis and calculation engine based on memory; 1.2 Spark && Hadoop SParkHadoop1.Scala development, fast, universal and extended big data analysis engine1. Java development, an open source framework for storing massive data on distributed server cl ...

1, Collection introduction 1) Scala's collections fall into three categories: sequence Seq, Set and Map. All collections are extended from Iterable Characteristics. 2) For almost all collection classes, Scala provides both variable and immutable versions, which are located in the following two places: Package Immutable set: ...

title: "geotools learning (I) quick start to IntelliJ" date: 2021-04-29 14:08:52 tags: [] published: true hideInList: false feature: isTop: false This guide will help you set up the IntelliJ IDE to use GeoTools and follow the rest of the GeoTools tutorial. geotools learning (I) quick start to IntelliJ Preparatory knowledge Thi ...

Original article publishing address: https://www.jianshu.com/p/d0e8b605c4ce Click "read the original text" or visit https://linkis.apache.org/#/ Learn more about Apache links Community developer: Maria Carrie GitHub : mindflow94   This article is mainly used to guide users to install and deploy Linkis and datasphere studio, and t ...

Multiple definition Type variables can have both upper and lower bounds. Written as: T >: Lower <: Upper There cannot be multiple upper bounds or multiple lower bounds at the same time; However, you can still require a type to implement multiple characteristics, like this: T <: Comparable[T] with Serializable with Cloneable Ther ...

1. Introduction to Scala 1.1 general Scala is a multi paradigm programming language based on JVM. Generally speaking, Scala is a functional object-oriented language running on the JVM. Scala can be widely used in various programming tasks. It can do everything from writing small scripts to building giant systems. Because of this, Scala can pr ...

Process control Branch control if else   let the program execute selectively. There are three branches: single branch, double branch and multi branch Single branch Basic grammar if (Conditional expression) { Execute code block } Note: when the conditional expression is true, the code of () will be executed. case Deman ...

kafka's distributed, high throughput, high availability features and various message consumption modes can ensure the security of message consumption in a multi node cluster environment: that is, to prevent each message from missing processing or repeated consumption. In particular, the exactly once consumption strategy can ensure that each mes ...