Scala functional programming under functional data structure
previously on
Guide to functional programming in Scala
Scala functional programming (2) introduction to scala basic syntax
scala functional programming (3) scala sets and functions
Scala functional programming (four) functional data structure
1.List code analysis
The content introduced today is mainly to supplement the scala functional data st ...
Posted by stev979 on Thu, 19 Dec 2019 03:45:09 -0800
Real time log analysis by Flume+Kafka+SparkStreaming+Redis+Mysql ip access times
Novice learning, if there are mistakes, please correct, thank you!
1. Start zookeeper and kafka, and set a topic as test fkss. For the convenience of observation, I added it through kafka manager
2. Configure Flume and start it. The listening file is / home / czh / docker-public-file/testplume.log, which is sent to kafka
a ...
Posted by ksduded on Sat, 14 Dec 2019 10:51:38 -0800
[four Twirl template engine] 3. Common templates
Now let's look at the typical usage of templates.
layout
Now declare a view / main.scala.html template as the main template:
@(title: String)(content: Html)
<!DOCTYPE html>
<html>
<head>
<title>@title</title>
</head>
<body>
<section class="content">@content</section> ...
Posted by Tryweryn on Sun, 08 Dec 2019 07:13:13 -0800
Scala defines arrays, enhances for traversing Scala arrays, unitl generates subscripts traversing Scala arrays, array conversion, array common algorithms 05
1 fixed length array and variable length array
Format of fixed length array definition:
val arr = new Array[T] (array length)
Variable length array definition format:
val arr = ArrayBuffer[T]()Note that you need to import the package: import scala.collection.mutable.ArrayBuffer
The code is as follows
import scala.colle ...
Posted by sashi34u on Sat, 16 Nov 2019 07:37:04 -0800
2. Principle and Use of spark--spark core
[TOC]
1. Some basic terms in spark
RDD: Elastically distributed datasets, the core focus of sparkOperators: Some functions for manipulating RDDapplication: user-written spark Program (DriverProgram + ExecutorProgram)job: an action class operator triggered operationstage: A set of tasks that divide a job into several stages based on dependencie ...
Posted by FeeBle on Fri, 15 Nov 2019 22:22:07 -0800
playframework - Tutorial
play framework 2.x is a framework developed with scala and java. It can't be said to be a framework, but a solution.
The advantages of play framework are as follows:
High efficiency of development and functional programming of scala.
Stateless and scalable.
Hot deployment, direct dynamic compilation of source code modificati ...
Posted by cbrian on Sun, 10 Nov 2019 07:15:19 -0800
Understanding closures in Scala
First of all, we need to distinguish the differences between Scala functions and methods, which are two different concepts in scala. Only when we understand these two concepts can we understand the currification.
Method
scala> def add(x:Int, y: Int) = x + y
add: (x: Int, y: Int)Int
scala> add(1, 2)
res0: Int = 3
function ...
Posted by sactown on Tue, 05 Nov 2019 08:25:54 -0800
flink dynamic broadcast status
flink dynamic broadcast status notes
1. outline
Often we need dynamic matching rules when doing the flink task calculation, but we can't redeploy the service every time we modify it, so we need to use the dynamic broadcast state mechanism of flink to deal with our rule changes in real time. ...
Posted by spectsteve7 on Sat, 02 Nov 2019 17:44:14 -0700
Chapter 3 array related operations in notes of quick learning scala Second Edition
Fixed length array
Array of constant length, array of Scala:
val nums = new Array[Int](10)
//Array of type Int, length 10, initial value 0
nums(0)
//Array access with parentheses
Variable length array
Similar to ArrayList in Java, scala uses ArrayBuffer
val emptyBuffer = ArrayBuffer[Int]()
...
Posted by jcombs_31 on Tue, 29 Oct 2019 14:56:23 -0700
Flink development issues summary
When installing through brew on mac system, the local default installation address is / usr / local / cell / Apache Flink / 1.5.1
1. Can I call graph algorithm in flink?
It can be called in dataSet, and it needs to write its own method in dataStream. It can be implemented in scala by itself, just by r ...
Posted by Rommeo on Sun, 27 Oct 2019 03:13:17 -0700