implicit object, then import the function of this type, and then the man can also be used under the function of implicit object in the implicit conversion.
Implicit parameters, which can be used to transmit the parameters for an implied number of variables.First write a function:def talk (name:string) (implicit content:string) = println (name + ":" + content), the 2nd is an implicit reference, and then the talk-side If there are no implicit parameters, the editor will report it! At this poi
3, hands-on generics in Scala generic generic classes and generic methods, that is, when we instantiate a class or invoke a method, you can specify its type, because Scala generics and Java generics are consistent and are not mentioned here. 4, hands on. Implicit conversions, implicit parameters, implicit classes in Scala Implicit conversion is one of the ke
Java version of the spark large data Chinese word segmentation Statistics program completed, after a week of effort, the Scala version of the spark
Large data Chinese Word segmentation Statistics program also got out, here to share to you want to learn spark friends.
The following is the final operation of the program
How to build a spark development environment using MAVEN step-by-step in IntelliJ idea, and write a simple wordcount instance of Spark based on Scala.
1. Preparatory workFirst you need to install JDK and Scala and development tools on your computer IntelliJ idea, this article uses the Win7 system, the environment is co
The collection mainly has list, set, Tuple, map, etc., we follow the hands-on practical way to learn. We create a list instance in the Eclipse IDE: Now let's look at the code implementation: In the source code, it is stated that the internal is the method of apply to complete the instantiation; In the same way we can instantiate set: You can also see the implementation of the set instantiation object at this point: Next we'll look at the set in the command-line terminal, first of all set:
5. Apply method and Singleton object in Scala to create a new class: As an additional point, the methods placed in object objects are static methods, as follows: Next look at the use of the Apply method: The above code always when we use "val a = Applytest ()" will cause the call of the Apply method and return the value of the method call, that is, the instantiated object of the applytest. C The lass can also be used by the Apply method, as shown
Install Scala and Spark in CentOS
1. Install Scala
Scala runs on the Java Virtual Machine (JVM). Therefore, before installing Scala, you must first install Java in linux. You can go to my article http://blog.csdn.net/xqclll/article/details/54256713to continue without install
Quick StartThis article describes how to use scala, java, and python to compile a spark click Mode Program. First, you only need to successfully build Spark on a machine. Practice: Enter the Spark root directory and enter the command: $ sbt/sbt package(Because of the Great Firewall of tianchao, the mainland China canno
Preface: Recently in the research Spark also has Kafka, wants to pass the data which the Kafka end obtains, uses the spark streaming to carry on some computation, but constructs the entire environment is really not easy, therefore hereby writes down this process, shares to everybody, hoped that everybody may take a little detour, can help everybody!Environment Preparation:operating system: ubuntu14.04 LT
Spark provides an interactive shell that enables us to point to point (Original: ad hoc) data analysis. If you've already used R,python, or a shell in Scala, or an operating system shell (such as bash), or a Windows command prompt, you'll be familiar with Spark's shell.But in fact, the spark shell is different from most other shells, and most of the other shells
Description, since Spark was written in Scala. Therefore, it is best to use Scala whether you are looking at the source code or writing spark-related codes. Then, as a programmer, the first thing to do is to sharpen the sword in hand. That's creating a code environment for writing
Install jdk1.7.0_60 and scala2.10.4 on the development machine and configure the relevant environment variables. Many online data, installation process ignored. In addition, Eclipse uses Luna4.4.1,idea to use the 14.0.2 version.1. Eclipse Development Environment Building1.1. Install the Scala pluginInstalling the Eclipse-scala-plugin plug-in, http://scala-ide.org
Lesson 2nd: Scala's object-oriented mastery and spark source readingContents of this issue:1 Scala's class, object in real combat2 abstract classes and interfaces in Scala3 comprehensive case and spark source code analysisOne: Define ClassClass hiscala{private var name = "Spark"Def sayname () {println (name)}def getName = Name}In
(transformation) and the Action (action). The main difference between the two types of functions is that transformation accepts the RDD and returns the RDD, while the action accepts the RDD to return the non-rdd.The transformation operation is deferred, meaning that a conversion operation that generates another RDD from an RDD is not performed immediately, and the operation is actually triggered when there is an action action.The action operator triggers sp
Java switch-case (pair value)Scala is not only for values, but also for types, collections (map,list metadata matching), Object,classScala uses a lot of pattern matching (Match case)Scala's pattern match, which differs from the Java switch case:1. Not only can match the value, can match type2. Can match the collection of arraysAn array of the same array, the same length, and an array beginning with an elementAutomatic variable assignment for arrays of
1. Download spark installation package from the official website and extract it to your own installation directory (the default has been installed JDK,JDK installed to find it yourself); Spark Official website: http://spark.apache.org/downloads.html
2. Enter the system command line interface, enter the installation directory, such as "/installation directory/spark
Learn Spark 2.0 (new features, real projects, pure Scala language development, CDH5.7)Share--https://pan.baidu.com/s/1jhvviai Password: SirkStarting from the basics, this course focuses on Spark 2.0, which is focused, concise and easy to understand, and is designed to be fast and flexible.The course is based on practical exercises, providing a complete and detail
SparkstreamingcontextWe create Sparkstreamingcontext objects in a configuration-based manner:The third step, Create spark streaming input data Source:We configure the data source as local port 9999 (note that port requirements are not being used):Fourth Step: We're like the Rdd . programming, based on Dstream for programming because of the Dstream It's an rdd . generated template, in spark streaming before
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