Learn key phrases: Array.reduce Array.prototype.reduce reduce method Override reduce method 1. Write in front Many students (referring to myself) have no difficulty in learning other array expansion methods, but when it comes to the reduce method, they will appear stupid, so today I will quickly explain this method clearly. In fact, all array expansion methods […]
Tag: reduce
08 | How does MapReduce allow data to complete a journey?
In the last issue, we talked about the MapReduce programming model that divides the big data calculation process into two stages: Map and Reduce. Let’s review it first. In the Map stage, each data block is assigned a Map calculation task, and then all the map output keys are processed. Merge, the same Key and […]
6.824 map-reduce
I recently joined the company, so I have some free time to write something and my own thoughts. The level is relatively good, and we will make progress together with everyone. In line with the principle of grasping the main contradiction, this article does not involve tutorial content such as environment configuration. I believe that […]
hadoop mapreduce api calls WordCount native and cluster code
Run code natively package com.example.hadoop.api.mr; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.Text; import org.apache.hadoop.mapreduce.Job; import org.apache.hadoop.mapreduce.Mapper; import org.apache.hadoop.mapreduce.Reducer; import org.apache.hadoop.mapreduce.lib.input.FileInputFormat; import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat; import java.io.IOException; public class WordCount { /** * Text: refers to StringWritable * (LongWritable, Text) Input on the map side: these two parameters will never change, Text: text data, LongWritable: offset (offset […]
Powerful functions in Python: map(), filter() and reduce()
Get more information Personal website: Brother Tao talks about Python Python is a feature-rich programming language that provides many built-in functions to simplify various programming tasks. In Python, map(), filter() and reduce() are a set of very useful functions that allow iterable objects to be Perform operations to transform, filter, and accumulate data. This article […]
Javascirpt encapsulates xhr to upload multiple pictures, and solves the problem that the formdata backend only accepts one picture, and uses the prototype chain to encapsulate it to reduce resource waste and improve performance.
The prototype chain of the function is used here to encapsulate each shared function and privileged method to access private data. <html> <head> <meta http-equiv=”Content-Type:text/html;charset=utf-8″/> <title></title> <script type=”text/javascript” src=”common.js”></script> <style type=”text/css”> #preview {<!– –> display: flex; flex-wrap: wrap; width: 580px; padding: 10px; justify-content: start; } .icon-po {<!– –> overflow: hidden; position: relative; width: 150px; height: […]
The difference between reduceByKey and groupByKey in Spark [Super detailed]
Article directory Preface 1. Let’s look at the conclusion first 1. From the perspective of Shuffle 2. From a functional perspective 2. Examples and drawings 1. What are the functions implemented? 1).groupByKey implements WordCount 2).reduceByKey implements WordCount 2. Draw a picture to analyze the difference between the two implementation methods. 1) groupByKey implements WordCount 2).reduceByKey […]
Reduce Kubernetes cluster costs with kube-downscaler
New Titanium Cloud Server has shared with you a total of 772 pieces of technical information. Introduction Kube-downscaler is an open source tool that allows users to define when pod resources in Kubernetes are automatically scaled down. This helps reduce infrastructure costs by reducing resource usage during off-peak hours. In this article, we will detail […]
Android APK slimming practice: How to reduce the size of the second slimming? (4M-2.9M)
Before losing weight Because size restrictions are usually taken into consideration, a lot of work has been done. The current status is listed below: 7.3M (Debug version) and 6.5M (Release version). Turn on minifyEnabled. Turn on shrinkResources. Large irrelevant libraries have been removed. Images and code have gone through a rough round of cleaning. Start […]
Use Hystrix to implement request merging and reduce server concurrency pressure
1. Introduce Hystrix <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-hystrix</artifactId> </dependency> 2. Enable Hystrix function on the startup class @EnableHystrix 3. Request to merge the implementation code import com.bzcst.bop.oms.orm.model.po.Product; import com.bzcst.bop.oms.orm.service.ProductService; import com.netflix.hystrix.contrib.javanica.annotation.HystrixCollapser; import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand; import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty; import com.netflix.hystrix.contrib.javanica.conf.HystrixPropertiesManager; import lombok.extern.slf4j.Slf4j; import org.springframework.stereotype.Service; import javax.annotation.Resource; import java.util.List; import java.util.concurrent.Future; /** * @author Xiang Zhenhua * @date 2023/10/26 14:37 */ […]