Go, how to become a gopher, and find work related to go language in 7 days, Part 1

️ Before learning

The goal of this series of blogs is 7 Learn to Go Language , And find a Go Related work , There must be some preconditions , That is, the front technical point .

You need ：

• Have a programming language foundation ,Python,PHP,C# …… Fine ;
• be familiar with Linux Basic operation , At least build small projects on the server side ;
• Skilled computer operation , Typing speed is not bad .

With these foundations , Only when 7 Master quickly within days Go Language , Otherwise, it is difficult to do .

️ Go The background of

To learn a language, you must first understand its background , Among them, we can find the cause of the language , There are also problems solved by the core of the language .

Go It's open source. , And in 2007 R & D started in ,2009 In open source ,2012 Released in 1.0 edition , As a language , Very young .

and Go Language is Unix The author of ,C The author of language , And Google's V8 The engine is built by this person , also Go Is launched by Google , So back to the mountain .

Go The mascot of is a gopher （ Its scientific name is gopher , chipmunk , English name Gopher）, So a lot of Go The openers of call themselves Gopher.

Go The official website of language

https://golang.google.cn/learn/

Go Linguistic gihub

https://github.com/golang/go

These two sites are the key locations for future learning work to obtain first-hand materials .

Some more Go Language learning Chinese official website , You can search by yourself through the search engine , There are many communities , The learning stage can absorb a large amount .

Go Of hello world

I downloaded the latest version on the official website , In principle, it is better to choose a lower version in the learning stage , Relatively pure , But this issue is a quick start , So go straight to the new .

Install it and go to the next step , Enter the installation waiting page .

Enter... After installation CMD You can view its version number , Use the following command ：

C:\Users\Administrator>go version
go version go1.18.4 windows/amd64

Next, write directly Hello World Code ,Go The suffix of the language is .go , You can create one in any local directory 01_demo.go file .
After installation , Found in Go Wrapped in VSCode Some functions are integrated in .

If prompted that it needs to install extensions , You can supplement yourself .

Hello World The code is very simple , Use the following command .

package main

import "fmt"

func main() {
    
	fmt.Println("Hello,World")
}

The operation is also very simple , Use go run file name that will do .

Because we already have the foundation of other languages , Therefore, the knowledge points at the grammatical level can be directly summarized .

First line code package main , Define package name ,Go The syntax requires that you specify which package the file belongs to in the first line of the non comment .

This line of code is import Go Linguistic main package ,main The packaging is special , It defines an independent executable program , Not the library . stay main In bag , function main It's also special , It is where the program starts .

Go All files of the language need to specify their packages （package）, There are two types of packages , One is to main package , Use package main Import , Another kind of right and wrong main package , Use package Package name Import , stay Go Use in package Manage source files ,package Must be in a folder , And there can only be one under this folder package.

Lines of code import "fmt" Indicates the need to use fmt package , That is, call its variables 、 Functions and so on , This package is used to format I/O, Input and output functions .

Lines of code func main() Is the start function of the program , Every executable program must contain main .

Lines of code fmt.Println("Hello,World") , Output function , You can see fmt The package is called , According to the experience of other languages Println Means line break , Print No line break .

Here we have also experimented with an operation , When the braces { perhaps } On a single line , There will be errors .

func main()
{
    
	fmt.Println("Hello,World")
}

Except as mentioned above go run file name function Go Out of program , You can also use go build file name take Go Code compiled as exe Program .

PS F:\go_learn> go build .\01_demo.go
PS F:\go_learn> ls
 Catalog : F:\go_learn
Mode                LastWriteTime         Length Name
----                -------------         ------ ----
-a----        2022/7/20     11:41        1892352 01_demo.exe
-a----        2022/7/20     10:42             79 01_demo.go

️ Go Grammatical details

stay Go In language , A line is a statement , There is no need to use ; ending , In fact, in practice, you can also write multiple sentences on one line , And then put ; On use , But basically no one does this .

func main() {
    
	fmt.Println("Hello");fmt.Println("World")
}

stay VSCode in , It is automatically formatted .

notes
The notes are relatively simple , Single line use // , Use multiple lines /**/ .

identifier
stay Go in , Used to name variables , function , Type of content , It's an identifier , It needs letters , Numbers , Underline composition , And the first character must be a letter or underscore , It can't be a number , This is also required by other languages , No learning difficulty .

keyword
stay Go in , Yes 25 Keywords or reserved words , These generally do not need special memory , But when you ask for your own identifier to be named , Try to convey the meaning of words .

Declaration of variables
Go Languages are static types , Variable declarations need to have explicit types , The syntax format is as follows ：

var name type

among var Is the key word , name Is a variable name. , type It's the type of variable .

Go The basic types of language are ：

• string
• int、int8、int16、int32、int64
• uint、uint8、uint16、uint32、uint64、uintptr
• byte（uint8 Another name for ）
• rune （int32 Another name for ）
• float32、float64
• complex64、complex128
• bool

After the variable is declared , The system automatically assigns a zero value , for example int The type is 0,float The type is 0.0 ……

The naming standard follows the small hump naming method , for example myName,xiaomingAge.

String concatenation and string formatting
Grammar is consistent with other languages , + Express connection , When formatting strings , %s , %d Represent string and number respectively , The formatting function is as follows ：

package main

import "fmt"

func main() {
    
	var str_format = " Numbers ：%d, character string ：%s"
	var new_str = fmt.Sprintf(str_format, 100, " Eraser ")
	fmt.Println(new_str)
}

️ After learning

This blog is just Go Starting hand type , The next one is coming ~

You are reading 【 Dream eraser 】 The blog of
Finished reading , You can praise it with a little hand
Find the error , Correct it in the direct comment area
The second part of the eraser 696 Original blog

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