MySQL learning (19) | process control structure

Process control structure Sequence, branch, cycle describe Sequential structure Program execution from top to bottom Branch structure The program selects one of two or more paths to execute Cyclic structure On the basis of satisfying certain conditions, the program repeatedly executes a piec ...

Posted on Sat, 15 Feb 2020 22:48:02 -0800 by Option

Media query, responsive page

For mobile page, there are two implementation schemes:1. The PC side page and mobile side page of the website are completely separated, and different pages are returned to users according to the type of access device (this scheme is adopted by most domestic websites at present).2. Responsive page layout: the page itself can mak ...

Posted on Sat, 15 Feb 2020 10:32:11 -0800 by vishwavivek

Core data: the fastest way to delete all instances of an entity

I am using Core Data to keep the results of web service calls locally. Web services return the complete object model for "cars" - maybe 2000 (and I can't have web services return less than one or all cars). The next time I open my application, I want to refresh the Core Data persistent copy by invoking the Web services of all cars ...

Posted on Sat, 15 Feb 2020 06:52:20 -0800 by emma57573

Target detection in Python

I. Preface From learning single-chip computer and C language to learning CV and Python, I got a lot of help in CSDN, Jianshu, blog Park and github, so I also want to share some of my own small things to you, hoping to help others. mark, the first blog to record life. 2, Image detection steps 1. Read two pictures The first one is the small objec ...

Posted on Sat, 15 Feb 2020 05:54:52 -0800 by philicious

A brief look at the principle of ThreadPoolExecutor

The function of thread pool is not to say much, but to solve two kinds of problems: first, when a large number of asynchronous tasks are executed, thread pool can provide better performance; when not using thread pool, whenever asynchronous tasks need to be executed, a thread needs to be executed directly, and the creation and destruction of th ...

Posted on Sat, 15 Feb 2020 05:45:50 -0800 by zipp

Pile up study notes and 1098 insertion or head sort (25 points)

1. Definition of heap: The heap is a complete binary tree. It can be divided into large top heap (the value of the parent node is greater than or equal to the value of the child node) and small top heap (the value of the parent node is less than or equal to the value of its child node). 2. Storage o ...

Posted on Fri, 14 Feb 2020 08:22:34 -0800 by shrike202

Time operation (implemented in C + +)

Experimental principle Rules and application of operator overloading Experimental content Title: design and implement a time class and its related operations. Requirement: Time class includes hour, minute and second. Time, minute and second can be read and set. Format time HH: MM: SS can be ...

Posted on Fri, 14 Feb 2020 07:36:15 -0800 by wakenbake

Exploratory data analysis of multiple factors with the method of basic statistics

Before the establishment of machine science model, we often do exploratory factor analysis on the characteristics we have. Exploratory factor analysis can be divided into single factor analysis and multi factor analysis. Single factor analysis is mainly used to analyze a certain feature. Statistical ind ...

Posted on Fri, 14 Feb 2020 06:30:32 -0800 by jpmoriarty

Simple understanding of ArrayList source code

ArrayList 1. Create ArrayList list1 = new ArrayList(); An empty array is created by default private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {}; public ArrayList() { this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA; } 2. Execute list1.add(1); public boolean add(E e) { ensureCapacityIntern ...

Posted on Thu, 13 Feb 2020 10:01:59 -0800 by bdcode

PTA freshman training competition - 4

The sound of the cello is like a river. The left bank is my unforgettable memory. The right bank is my bright time to hold. The flowing in the middle is my slight sadness every year. 7-1 year of birth The above is a wonderful post on Sina Weibo: "I was born in 1988, and only when I was 25 di ...

Posted on Thu, 13 Feb 2020 04:04:41 -0800 by mark_18