1. Characteristics of Map interface implementation class 1)Map and Collection exist side by side. Used to save data with mapping relationships: Key-Value 2) The key and value in the Map can be any reference type data and will be encapsulated into the HashMap$Node object. 3) Keys in Map are not allowed to be repeated 4) […]
Tag: Collection
reactive and effect, dependency collection triggers dependencies
The project has been initialized through the previous article and integrated ts and jest. This article implements the reactive method in the reactive module in Vue3. Prerequisite knowledge If you are proficient in Map, Set, Proxy, and Reflect, you can skip this part directly. Map Map is a collection used to store key-value pairs and […]
[Python] collections module
The collections module in Python contains some container data types. import collections [x for x in dir(collections) if not x.startswith(‘_’)] # result: [‘ChainMap’, ‘Counter’, ‘OrderedDict’, ‘UserDict’, ‘UserList’, ‘UserString’, ‘abc’, ‘defaultdict’, ‘deque’, ‘namedtuple’] 1. collections.ChainMap() [Search multiple dictionaries] Search multiple dictionaries in the order in which they appear. m=collections.ChainMap(Dictionary 1, Dictionary 2, Dictionary 3,…): manages multiple […]
Experiment 5 Temperature collection and keyboard scanning
1. Experimental purpose *Master the method of controlling interrupts and timers in C51 *Master the principles and methods of using CH451 for keyboard input *Master the interface and programming of DS18B20 temperature sensor 2. Experimental equipment *MCU experiment box *CH451 display module *Temperature acquisition module (at the lower left of the SWITCH module area of […]
ZooKeeper+Kafka+ELK+Filebeat cluster construction to realize large batch log collection and display
The general process: After collecting the logs of the nginx server (web-filebeat) through filebeat, store them in the cache server kafka, and then logstash to the kafka server to retrieve the corresponding logs. After processing, they are written to the elasticsearch server and displayed on kibana. 1. Cluster environment preparation 4c/8G/100G 10.10.200.33 Kafka + ZooKeeper […]
java geotools shpfile to featureCollection
Article directory A brief description maven dependencies Sample code Brief description Convert shpfile to featureCollection maven dependencies <dependency> <groupId>org.geotools</groupId> <artifactId>gt-shapefile</artifactId> <version>27.0</version> </dependency> <dependency> <groupId>org.geotools.jdbc</groupId> <artifactId>gt-jdbc-postgis</artifactId> <version>27.0</version> </dependency> <dependency> <groupId>org.geotools</groupId> <artifactId>gt-referencing</artifactId> <version>27.0</version> </dependency> <dependency> <groupId>org.geotools</groupId> <artifactId>gt-render</artifactId> <version>27.0</version> </dependency> <dependency> <groupId>org.geotools</groupId> <artifactId>gt-coverage</artifactId> <version>27.0</version> </dependency> <dependency> <groupId>it.geosolutions.imageio-ext</groupId> <artifactId>imageio-ext-utilities</artifactId> <version>1.4.4</version> </dependency> <!– https://mvnrepository.com/artifact/com.conversantmedia/disruptor –> <dependency> <groupId>com.conversantmedia</groupId> <artifactId>disruptor</artifactId> <version>1.2.15</version> </dependency> […]
List series collection and Set series collection
1. List series collection 1. Features 2. Unique methods 2. Traversal of List collection Because the List collection has an index, it can be traversed using a for loop These functions can be used by List implementation classes (LinkList, ArrayList). 3. The underlying principle of the ArrayList collection 1.Principle 2. Applicable scenarios 4. The underlying […]
The most complete collection of love codes in the history of C language and C++, with color flashing, character filling, and source code attached
The first type: red love code Go directly to the code: #include<stdio.h> #include<Windows.h> int main() {<!– –> system(” color 0c”);//Design program color printf(“It is a very happy thing to meet you, I love you!!!\\ “);//Print text \t float x,y,a;//define variables x,y,a \t for(y=1.5f;y>-1;y-=0.1f) {<!– –> for(x=-1.5f;x<1.5f;x + =.05f){<!– –> a=x*x + y*y-1; putchar(a*a*a-x*x*y*y*y<0.0f?’x’:’ ‘); } […]
Collection framework and the data structure behind it
Table of Contents 1 Introduction 2. The meaning of learning 2.1 Advantages and functions of Java collection framework 3. Interface 3.1 Basic relationship description 3.2 Collection interface description 3.3 Collection common methods 3.4 Collection example 3.5 Map interface description 3.6 Map example 4. Implementation 5.Framework 5.1. Use of collection framework 1. Introduction Java collection framework […]
Java collection ConcurrentHashMap What is the difference between how to use each method and HashMap through source code analysis?
Table of Contents Hello friends, today I will analyze the thread-safe hashmap. The main features of ConcurrentHashMap include: ConcurrentHashMap example Let’s take a look at the source code of the size(), containsKey(), and replace() methods. Okay, let’s continue to look at the replace method. The first thing is to check whether a null pointer exception […]