Programmer Think

1. Introduction In the process of project development, when some data is written, if it already exists, it can be overwritten. This can prevent multiple repeated writes to the only key conflict and error reporting. Here are two examples of using saveOrUpdate in MyBatis configuration files <!-- Single data saving --> <insert id="saveO ...

1, Introduction 1 PCA PCA (Principal Component Analysis) is a commonly used data analysis method. PCA is a method that transforms the original data into a group of data representation with linear independence of each dimension through linear transformation. It can be used to extract the main feature components of data and is often used for dim ...

definition The responsibility chain model is a model of "handling" events in a hierarchical process, which may be a little vague, For example: suppose I have a restaurant in which there are three roles of "apprentice, chef and chef". When customers come to the restaurant for dinner, they first hand over the dishes to be coo ...

1. Background Since the official version of rockdoc is available in the cloud environment, rockdoc has to be used as the real-time image of the company's own version, but it is not installed in the cloud environment. According to the release of StarRocks official website, ARM environment is supported in version 2.0, so it starts to scratch the ...

Calculation of protein molecular weight for Rosalind programming problem. Calculating Protein Mass Problem In a weighted alphabet, every symbol is assigned a positive real number called a weight. A string formed from a weighted alphabet is called a weighted string, and its weight is equal to the sum of the weights of its symbols. The standar ...

MySQL MHA 1, MHA concept MHA (MasterHigh Availability) is a set of excellent software for failover and master-slave replication in MySQL high availability environment.The emergence of MHA is to solve the problem of MySQL single point.During MySQL failover, MHA can automatically complete the failover operation within 0-30 seconds.MHA can e ...

Scaffolding The purpose of scaffolding is to quickly build the basic structure of the project and provide project specifications and conventions. At present, the scaffolds commonly used in daily work include Vue cli, create react app, angular CLI and so on. They all complete the rapid construction of content through simple initialization comma ...

Project scenario: The background of the project is the monitoring and management platform and the alarm configuration section. It is necessary to query and return multiple data information. Among them, it is necessary to optimize the query and return function of subscribers. The original one can only enter one subscriber name for query and opt ...

js to judge the number of Chinese characters //****************************************************************  //*Name: DataLength //*Power: calculate the length of data //*Entry parameter: fData: data to be calculated //*The length of the exit is F 2 (the length of the non Unicode parameter is F 2) //**************************************** ...

When I see the logistic regression classifier, my first reaction is that it's not a statistical logistic regression. In fact, it's the same. I've written about the practice of logistic regression before. I'll write it again under the framework of machine learning today. logistic regression is a supervised learning method that predicts class ...