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/**
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* Golang CHEATSHEET (中文速查表) - by chlins (created on 2018/02/14)
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* Version: 1, Last Modified: 2018/02/28 16:51
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* https://github.com/skywind3000/awesome-cheatsheets
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*/
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/**
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* Hello World
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*/
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package main
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import "fmt"
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func main() {
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fmt.Println("Hello World")
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}
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// go run main.go
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/**
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* 变量声明
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*/
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// 直接使用 := 来给一个未声明的变量赋值
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a := 1
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// 通过 var 变量名 数据类型 来声明
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var a int
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a = 1
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// 注意：使用var声明过的变量不可再使用 := 赋值
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/**
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* 常量
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*/
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// 常量直接使用 const 声明
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const a = 1 // golang 会自动推倒类型
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/**
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* 数据类型
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*/
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// 字符
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s := "hello"
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// 数值
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a := 1 // int
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b := 1.2 // float64
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c := 1 + 5i // complex128
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// 数组
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arr1 := [3]int{4, 5, 6} // 手动指定长度
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arr2 := [...]int{1, 2, 3} // 由golang自动计算长度
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// 切片
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sliceInt := []int{1, 2} // 不指定长度
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sliceByte := []byte("hello")
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// 指针
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a := 1
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point := &a // 将a的地址赋给point
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/**
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* 流程控制
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*/
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// for
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i := 10
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for i > 0 {
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println(i--)
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}
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// if else
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if i == 10 {
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println("i == 10")
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} else {
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println("i != 10")
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}
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// switch
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switch i {
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case 10:
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println("i == 10")
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default:
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println("i != 10")
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}
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/**
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* 函数
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*/
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// 以func关键字声明
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func test() {}
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// 匿名函数
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f := func() {println("Lambdas function")}
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f()
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// 函数多返回值
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func get() (a,b string) {
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return "a", "b"
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}
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a, b := get()
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/**
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* 结构体
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*/
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// golang中没有class只有struct
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type People struct {
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Age int // 大写开头的变量在包外可以访问
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name string // 小写开头的变量仅可在本包内访问
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}
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p1 := People{25, "Kaven"} // 必须按照结构体内部定义的顺序
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p2 := People{name: "Kaven", age: 25} // 若不按顺序则需要指定字段
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// 也可以先不赋值
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p3 := new(People)
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p3.Age = 25
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p3.name = "Kaven"
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/**
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* 方法
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*/
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// 方法通常是针对一个结构体来说的
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type Foo struct {
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a int
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}
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// 值接收者
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func (f Foo) test() {
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f.a = 1 // 不会改变原来的值
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}
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// 指针接收者
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func (f *Foo) test() {
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f.a = 1 // 会改变原值
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}
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/**
|
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|
|
|
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* 并发 golang 的特别之处
|
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*/
|
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|
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// go 协程
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go func() {
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time.Sleep(10 * time.Second)
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println("hello")
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}() // 不会阻塞代码的运行 代码会直接向下运行
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// channel 通道
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c := make(chan int)
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// 两个协程间可以通过chan通信
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go func() {c <- 1}() // 此时c会被阻塞 直到值被取走前都不可在塞入新值
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go func() {println(<-c)}()
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// 带缓存的channel
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bc := make(chan int, 2)
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go func() {c <- 1; c <-2}() // c中可以存储声明时所定义的缓存大小的数据，这里是2个
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go func() {println(<-c)}()
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