First, let’s introduce what attributes the django model has: Let’s look at an example first: The Meta of the Django model class is an internal class, which is used to define the behavior characteristics of some Django model classes. The following…
Method 1: Automatic creation Method 2: Purely manual creation Method 3: Semi-automatic creation
After introducing the AutoNavi map in index.html, it reported the error’AMapUI’ is not defined,’AMap’ is not defined’ First, I tried to put the reference of the Gaode map in the body and found that it was useless, and then found…
It is often necessary to judge data during business processing. Here we introduce the judgment methods of empty objects and empty arrays. Judgment of empty array Null object judgment The isPrototypeOf() method is used to test whether an object exists…
ES6 provides a new data structure, Set, which is similar to an array, but the values of the members are unique and there are no duplicate values; Set itself is a constructor that generates the Set data structure. Array de-duplication…
ES6 provides a new data structure Set. It is similar to an array, but the values of the members are unique and there are no duplicate values.
Preface DartIt is a computer programming language developed by Google. It is used for webthe development of servers, mobile applications and other fields . It was Dartunveiled in 2011. At the DartDeveloper Summit in May 2015 , it unveiled a…
Basic Grammar Shorter expressions There is no separate this Before the arrow function appears, each new function defines the this value of this function according to how it was called. If the function is a constructor, this pointer points to…
Noun convention In general, there are the following noun conventions. Promise (lowercase initials) object refers to “Promise instance object” Promise initial capitalization and singular form for “Promise constructor” Promises is capitalized and pluralized to refer to the “Promises specification” So…
