• [regular expression] matching times of basic reference books


    *. grouping Before we talk about the number of matches, let’s talk about the others.Use parentheses () to wrap the character content and make it a subexpression. After matching, in addition to the total matching result, the subexpression matching result will also be stored in memory.Here, the function of brackets is similar to that of […]

  • Introduction to strings package of go string


    Strings package Usually in the development process, there are many ways to deal with strings, such as segmentation, removal, replacement and so on. These are provided by strings package. Let’s see the use of strings package division s := “I_Love_golangCaff” res := strings.Split(s, “_”) for value := range res { fmt.Println(value) } I LoveGolangcaff / […]

  • Go gadget series — retrial mechanism


    A series of articles: Go gadget series — determine whether an element exists in an array Go gadget series — retrial mechanism Go gadget series — type conversion Requirement: if we want a code to be retried several times in case of execution failure and then throw an error, how to implement it in go? […]

  • Database ‖ Hadoop namenode performance troubleshooting process sharing


    With the development of the domestic Internet industry, although the mega cluster is not as rare as it was a few years ago, it is also rare, especially the opportunity of performance troubleshooting involving the mega cluster is even rarer. And this time, I have carried out the performance troubleshooting of Hadoop namenode with a […]

  • The use of rabbitmq in ketchup message queue


    Ketcup git address: https://github.com/simple-gr/ketchup Rabbitmq installation 1.docker pull rabbitmq:management 2.docker run -itd –name rabbitmq –restart=always -p 5672:5672 -p 15672:15672 -e RABBITMQ_DEFAULT_USER=admin -e RABBITMQ_DEFAULT_PASS=qwe123QWE rabbitmq:management RABBITMQ_ DEFAULT_ User: default login name. RABBITMQ_ DEFAULT_ Pass: default login password three http://ip : 15672 web page login       This page indicates that the installation is successful Configuring […]

  • Introduction to pandas (1)


    Data analysis and processing library import pandas as pd df=pd.read_csv(“./pandas/data/titanic.csv”) df.head (N) Read the first n rows of data df.head(6) df.info () get a brief summary of the dataframe df.info() <class ‘pandas.core.frame.DataFrame’> RangeIndex: 891 entries, 0 to 890 Data columns (total 12 columns): # Column Non-Null Count Dtype — —— ————– —– 0 PassengerId 891 […]

  • Introduction and characteristics of algorithm time frequency


    Time complexity of the algorithm Time frequency What is time frequency Time frequency: the time spent by an algorithm is in direct proportion to the execution times of the statements in the algorithm. The number of statements executed in an algorithm is called statement frequency or time frequency. T (n). [example] Examples – basic cases […]

  • How to protect your music works from being stolen and make anti-theft watermark clips with fl


    It’s said that there are many people who are popular. I wonder if you still remember that the popular song “wolf disco” in 2019 was involved in plagiarism and even sent a lawyer’s letter.Of course, this matter has been solved, and my uncle has proved his innocence. But the original author’s protection of his music […]

  • Interesting redis: the cache is full. What should I do?


    Redis is a memory database. When the memory used by redis exceeds the limit of physical memory, the memory data will be exchanged with disk frequently, which will lead to a sharp decline in redis performance. Therefore, in the production environment, we limit the memory size by configuring the maxmoey parameter. When the actual memory […]

  • Spring cloud followers summary


    Swan cloud is encapsulated based on spring cloud, which is an ordered collection of a series of frameworks. The development mode of spring boot is used to simplify the development of distributed system infrastructure, such as service discovery, registration, configuration center, message bus, load balancing, circuit breaker, data monitoring, etc. (only a part is listed […]

  • Php-fpm tuning: use “PM static” to maximize your server load


    Let’s quickly learn how to set up php-fpm to achieve high throughput, low latency and stable use of CPU and memory. By default, most settings set php-fpm PM (Process Manager) todynamic , or when you have a problem with available memory, it is recommended that you use itondemand. Next, let’s start withphp.netCompare these two management […]

  • Data structure file string search based on improved KMP algorithm


    Title Requirements Create a character file. Input the character file name and substring from the keyboard, the program first obtains the nextval array of substring, then uses the improved KMP algorithm to find the substring in the file, and finally displays the matching times of output substring in the file on the screen. If there […]