Python 程序员的 Golang 学习指南（III）: 入门篇

// 基础类型
布尔类型: bool
整型: int8，uint8，int16，uint16，int32，uint32，int64，uint64，int，rune，byte，complex128， complex64，其中，byte 是 int8 的别名
浮点类型: float32 、 float64
复数类型: complex64 、 complex128
字符串: string
字符类型: rune（int32的别名）
错误类型: error

// 复合类型
指针（pointer）
数组（array）
切片（slice）
字典（map）
通道（chan）
结构体（struct）
接口（interface）

break        default      func         interface    select
case         defer        go           map          struct
chan         else         goto         package      switch
const        fallthrough  if           range        type
continue     for          import       return       var

var a int
a = 2

// 或者
a := 2

// 同时定义多个变量
var (
    a int
    b bool
)

// 同时给多个变量赋值
a, b := 2, true

+    &     +=    &=     &&    ==    !=    (    )
-    |     -=    |=     ||    <     <=    [    ]
*    ^     *=    ^=     <-    >     >=    {    }
/    <<    /=    <<=    ++    =     :=    ,    ;
%    >>    %=    >>=    --    !     ...   .    :
     &^          &^=

for {
    // 实现无限循环，慎用！
}

// array
a := [3]int{ 1, 2, 3 } // 等价于 a := [...]int{ 1, 2, 3 }

// slice
s := make([]int , 3) // 创建一个长度为 3 的 slice
s := append(s, 1) // 向 slice 追加元素
s := append(s, 2)

// map
m := make(map[string]int) // 使用前必须先初始化
m["golang"] = 7

func myfunc(args ...int) {
    // TODO
}

// 可通过如下方式调用
myfunc(2)
myfunc(1, 3, 5)

func (file *File) Read(b []byte) (n int, err error)

// 我们可以通过下划线（_）来忽略某个返回值
n, _ := f.Read(buf)

func(a, b int) bool {
    return a < b
}

f := func(a, b int) bool {
    return a < b
}

func(a, b int) bool {
    return a < b
}(3, 4) // 花括号后直接跟参数列表表示函数调用

package main

import "fmt"

func main() {
    j := 5
    a := func() func() {
        i := 10
        return func() {
            fmt.Printf("i, j: %d, %d\n", i, j)
        }
    }()
    a()
    j *= 2
    a()
}

i, j: 10, 5
i, j: 10, 10

package main

import "fmt"

func main() {
    defer func() {
        fmt.Println("recovered:", recover())
    }()
    panic("not good")
}

type Name struct {
    First  string
    Middle string
    Last   string
}

type SimpleName string

func (s SimpleName) String() string { return string(s) }
// 或者
func (s string) NoWay()

def fib(n):
    a, b = 0, 1
    for i in range(n):
        a, b = b, a + b
        yield a

for x in fib(10):
    print x

print ‘done‘

package main

import "fmt"

func fib(n int) chan int {
    c := make(chan int)
    go func() {
        a, b := 0, 1
        for i := 0; i < n; i++ {
            a, b = b, a+b
            c <- a
        }
        close(c)
    }()
    return c
}

func main() {
    for x := range fib(10) {
        fmt.Println(x)
    }
}

from urlparse import urlparse, parse_qs
from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler

def auth_required(myfunc):
    def checkuser(self):
        user = parse_qs(urlparse(self.path).query).get(‘user‘)
        if user:
            self.user = user[0]
            myfunc(self)
        else:
            self.wfile.write(‘unknown user‘)
    return checkuser

class myHandler(BaseHTTPRequestHandler):
    @auth_required
    def do_GET(self):
        self.wfile.write(‘Hello, %s!‘ % self.user)

if __name__ == ‘__main__‘:
    try:
        server = HTTPServer((‘localhost‘, 8080), myHandler)
        server.serve_forever()
    except KeyboardInterrupt:
        server.socket.close()

package main

import (
    "fmt"
    "net/http"
)

var hiHandler = authRequired(
    func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "Hi, %v", r.FormValue("user"))
    },
)

func authRequired(f http.HandlerFunc) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        if r.FormValue("user") == "" {
            http.Error(w, "unknown user", http.StatusForbidden)
            return
        }
        f(w, r)
    }
}

func main() {
    http.HandleFunc("/hi", hiHandler)
    http.ListenAndServe(":8080", nil)
}

import urllib

def say_hi(usr):
    if auth(usr):
        print ‘Hi, %s‘ % usr
    else:
        print ‘unknown user %s‘ % usr

def auth(usr):
    try:
        auth_url = ‘localhost‘
        r = urllib.urlopen(auth_url + ‘/‘ + usr)
        return r.getcode() == 200
    except:
        return False

def sayhitest():
    # Test authenticated user
    globals()[‘auth‘] = lambda x: True
    say_hi(‘John‘)

    # Test unauthenticated user
    globals()[‘auth‘] = lambda x: False
    say_hi(‘John‘)

if __name__ == ‘__main__‘:
    sayhitest()

package main

import (
    "fmt"
    "net/http"
)

func sayHi(user string) {
    if !auth(user) {
        fmt.Printf("unknown user %v\n", user)
        return
    }
    fmt.Printf("Hi, %v\n", user)
}

var auth = func(user string) bool {
    authURL := "localhost"
    res, err := http.Get(authURL + "/" + user)
    return err == nil && res.StatusCode == http.StatusOK
}

func testSayHi() {
    auth = func(string) bool { return true }
    sayHi("John")

    auth = func(string) bool { return false }
    sayHi("John")
}

func main() {
    testSayHi()
}