当前位置:网站首页>The sixth training assignment
The sixth training assignment
2022-07-07 10:57:00 【m0_ sixty-three million five hundred and fifty-two thousand nin】
1. Operator
Operators are used to perform program code operations . Will operate on one or more operands
2. Control statement
We wrote javascript The code is carried out from top to bottom , Many times we want the code to execute as we want , For example, selectively execute some code , This requires the use of process control statements .
There are three kinds of process statements :
1. Process execution : From top to bottom , From left to right
2. Choose to perform : Branch selection
3. Loop execution : repeat
3. choice
3.1 Single choice
if( Conditions ){
Statement of body :
}
First, execute the condition
If the result is true, Then execute the statement body 1
If the result is false, Then execute the statement body 2
3.2 Multiple choice
if( Comparison expression 1){
Statement of body 1
}else if( Comparison expression 2){
Statement of body 2;
}else if( Comparison expression 3){
Statement of body 3;
}
3.3switch
Multiple if.....else And the value is constant , It can be used switch Replace :
switch( expression ){
case value 1;
Statement of body 1;
break;
case value 2;
Statement of body 2;
break;
default:
Statement of body n+1;
[break;]
}
break Prevent penetration , without break, Then continue to execute the following code , Until I met break Or complete the execution , But sometimes penetration is used
3.4 loop
The loop structure is used to repeat an operation , Simple to understand is to repeatedly execute the same type of code , He has many forms :
1.while: Execute before judge
2.do.....while: Judge before you execute , At least once
3.for:for( Initialization statement ; Judgment statement ; Control condition statement ){
Loop body statement ;
}
4. Dead cycle : Conditions are always there , For ever true, There will be a life and death cycle
5.break And continue
break: Stop this cycle
continue: Pause this cycle , Continue next time
4 Array
An array of data arranged in order , The position of each value has a number , The whole array is represented by brackets
4.1 To define an array
js There are three ways to define arrays in :
var arr=[1,2,3];
var arr=new Array(1,2,3);
var arr=new Array(size);
4.2 Basic operation
The length of the array can be determined by length Property to get , And you can change
4.3 Array traversal
Array traversal is to access each element in the array in turn ,js Provides three ways to traverse arrays :
1.for Loop traversal
2.for.....in
3.forEach
4. understand
4.4 The operation method provided by array
Array Object provides us with some methods , You can easily manipulate arrays
5. function
Functions as methods are pre-set blocks of code , It can be called repeatedly , According to the input parameters , Returns different values . Functions are also objects .
5.1 Function definition
There are three ways to define functions : Function declaration statement , Function definition expression ,function Constructors
5.2 Function declaration statement
function Function name ([ parameter list ]){
}
5.3 Function definition expression
Functions defined as expressions , The name of the function is unnecessary
var Variable name =function([ parameter list ])
5.4function Constructors
function Constructor accepts any number of arguments , But the last parameter is always regarded as a function body, also known as an expression , The previous parameters list the parameters of the new function
5.5 The parameters of the function
Sometimes, external data is required when a function is running , Different external data leads to different results , This kind of external data is called parameter , The parameters when defining are called formal parameters , The parameters when calling are called arguments
6. Function call
6.1 Commonly used call method
There is a return value that can be accepted by variables , If a function with no return value is accepted, it is unfined
2. Function call mode
3. Function call method
6.2return
Function execution may have a return value , Need to use return Statement to return the result to .return Statements are not necessary , If not, the function will not return any value
6.3 The scope of the function
Function scope : Global and local
1. The homonymy problem of global variables and local variables
2 When you define variables in a function , If not var keyword , After use, it will automatically become a global variable
边栏推荐
猜你喜欢
Deep understanding of Apache Hudi asynchronous indexing mechanism
打算参加安全方面工作,信息安全工程师怎么样,软考考试需要怎么准备?
VR development optimization
單調性約束與反單調性約束的區別 monotonicity and anti-monotonicity constraint
[actual combat] transformer architecture of the major medical segmentation challenges on the list --nnformer
JSON format query of MySQL
在线硬核工具
Pre knowledge reserve of TS type gymnastics to become an excellent TS gymnastics master
P1031 [noip2002 improvement group] average Solitaire
Unity script generates configurable files and loads
随机推荐
软考中级电子商务师含金量高嘛?
Find the root of equation ax^2+bx+c=0 (C language)
Schnuka: machine vision positioning technology machine vision positioning principle
Galaxy Kirin desktop operating system installation postgresql13 (source code installation)
Laya common script commands
Five simple and practical daily development functions of chrome are explained in detail. Unlock quickly to improve your efficiency!
I'd rather say simple problems a hundred times than do complex problems once
How much review time does it usually take to take the intermediate soft exam?
高级软考(网络规划设计师)该如何备考?
uniCloud
Using tansformer to segment three-dimensional abdominal multiple organs -- actual battle of unetr
Socket communication principle and Practice
Différences entre les contraintes monotones et anti - monotones
Summary of router development knowledge
MONAI版本更新到 0.9 啦,看看有什么新功能
路由器开发知识汇总
Unity script generates configurable files and loads
Deeply analyze the main contents of erc-4907 agreement and think about the significance of this agreement to NFT market liquidity!
Mendeley -- a free document management tool that automatically inserts references into papers
CSAPP Bomb Lab 解析