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Introduction to Manifest Manifest is a feature introduced by Scala 2.8 that allows compilers to obtain generic type information at runtime. stay JVM On the other hand, the generic parameter type T is "wiped" off at runtime, and the compiler treats T as an Object. So the specific information of T is not available; in order to get the ...

After installation of Ubuntu 16.04, 1. Install the commonly used software Sogou Input Method + Editor Atom + Browser Chome + Video Player vlc + Image Editor GIMP + Video Recording Software RcordMyDesktop. 2. Development Environment Configuration. JDK Environment Configuration+ Scala Environment Configuration + Noejs Environment Configuration + ...

Looking at the Kafka document recently, I found that Kafka has one. Log Compaction Functions we haven't noticed before, but they have high potential practical value. What is Log Compaction Every piece of data in Kafka has a pair of Keys and Value s, which are stored on disk and will not be preserved permanently, but delete the earliest written ...

1, array 1) Create arrays Create fixed-length arrays and variable-length arrays //Create a fixed-length array, use the new keyword, specify that the array generic type is Int, the length is 5, the default will initialize these five values for the default value of the specified type, such as Int, then the five default values ar ...

Based on the latest version of kafka_2.11-0.10.1.0, this paper describes the construction process of distributed Kafka cluster environment. Server List: 172.31.10.1 172.31.10.2 172.31.10.3 1. Download the kafka installation package Log on to Kafka http://kafka.apache.org/. Click the "Download" button on the left Select the corres ...

When we use Akka-http as a database data exchange tool, the data is stored in Entity in the form of Source[ROW,]. In many cases, besides data, we may need to transfer additional information, such as how to deal with the data. We can transfer additional custom messages through raw-header of Akka-http, which can be achieved through raw-header fil ...

Code: object Main extends App{ def Hθ(θ0:Double,θ1:Double,x:Double):Double=θ0+θ1*x def costFunction(θ0:Double,θ1:Double):Double={ val m=data.size var squreSum=0.0 data.foreach{case (x,y)=>{ squreSum+= (Hθ(θ0,θ1,x)-y)*(Hθ(θ0,θ1,x)-y) }} squreSum/(2.0*m) } val data=List((3,4),(2,1),(4,3),(0,1))//Data sets ...

Summary It is difficult to avoid the problem of SHP file storage when using Oracle Spatial. Although there are shp2sdo tools, they are not used to it, so this paper describes how to realize shp2sql conversion with geotools. Effect Implementation code package com.lzugis.geotools; import com.lzugis.CommonMethod; impo ...

1 Spark Operator 1.1 is divided into two categories 1.1.1 Transformation Transformation delays execution, which records metadata information and actually starts computing when the computing task triggers the Action. 1.1.2 Action 1.2 Two Ways to Create RDD RDD is created through the file system supported by HDFS. The ...

1. mapPartitionsWithIndex Create RDD with a specified partition number of 2 scala> val rdd1 = sc.parallelize(List(1,2,3,4,5,6,7),2) View partition scala> rdd1.partitions - As follows: res0: Array[org.apache.spark.Partition] = Array(org.apache.spark.rdd.ParallelCollectionPartition@691, org.apache.spark.rdd.ParallelColle ...