1 project construction
1.1 new project and operation
1.2 configure basic appearance according to project effect
2. Frame up
2.1 configure tabbar
3 get data from the background
3.1 package request component
3.2 build background application
4 home page
4.1 configure basic data of home page ...
Posted on Sat, 13 Jun 2020 03:34:05 -0400 by hash1
Based on the principal component analysis of the scores of 50 students in the table below, how many comprehensive variables can be selected to represent the scores of these students in 6 courses?
The data are as follows:
1. Data import and data standardization
> data=read.csv('D:/R languaga_ma ...
Posted on Sat, 13 Jun 2020 02:20:51 -0400 by php_east
Slow Query Log
Understanding slow queries
mysql's slow query is a type of log record provided by mysql that records statements whose execution time exceeds the set threshold.This time-out is configurable, and the default time-out is 10s, which is then written to the log.Then combined with explain to ...
Posted on Fri, 12 Jun 2020 22:13:07 -0400 by john9292
Chemistry is amazing. Here are the alkyl groups.
Suppose, as shown above, this alkyl group has six atoms and five chemical bonds, six atoms labeled 1-6, and then a pair of numbers a and b denotes that there is a chemical bond between atom A and atom b.This allows a description of an alkyl ...
Posted on Fri, 12 Jun 2020 21:22:51 -0400 by pgudge
1. What is a subquery
-- Requirements: Query who is in the development department
select * from emp;
-- Query by two statements
select id from dept where name='Development Department' ;
select * from emp where dept_id = 1;
-- Use subqueries
select * from emp where dept_id = (select id from dept where name='Marketing Department');
Posted on Fri, 12 Jun 2020 13:09:12 -0400 by JeffK
Cause: one day, my colleague's project connection pool burst
At first, I thought there was a long-running sql, but after checking the DB, I found that there was no such sql at all
Then I wonder if it is the calling of the third-party interface, which is suspended or not closed due to timeout. After ...
Posted on Fri, 12 Jun 2020 03:30:17 -0400 by ashbai
What is binary search tree
Binary Search Tree (also: Binary Search Tree, binary sort tree) it is either an empty tree or a binary tree with the following properties: if its left subtree is not empty, the values of all nodes on the left subtree are less than the values of its root nodes; if its right subtree is not empty, the values of all nodes ...
Posted on Fri, 12 Jun 2020 02:29:35 -0400 by WebbieDave
1, Transition animation
(1) Whether it's switching between components, or using v-if, v-show instructions to control the display of dom, as long as you want to achieve the animation effect, you must wrap it outside and give a name attribute to specify the use of the defined animation
<div id="ro ...
Posted on Fri, 12 Jun 2020 02:20:01 -0400 by bal bal
1. The relationship among artificial intelligence, machine learning and deep learning
What machine learning can do.
Recommended books for learningLearning objectives
2. What is machine learning
Machine learning is to automatically analyze and obtain laws (models) from data, and use laws to predict u ...
Posted on Fri, 12 Jun 2020 00:23:35 -0400 by Goose