关于go:Go-快速入门指南-命令行参数

命令行参数个数

调用 os 包即可。

获取参数个数, 遍历参数

package main

import (
    "fmt"
    "os"
)

func main() {fmt.Printf("Number of args is %d\n\n", len(os.Args))

    for _, arg := range os.Args {fmt.Println(arg)
    }
}

// $ go build main.go
// $ ./main -a -b --c -d
// 输入如下 
/**
  Number of args is 5

  ./main
  -a
  -b
  --c
  -d
*/

命令行参数解析和设置

调用 flag 包即可。

例子

设置参数

package main

import (
    "flag"
    "fmt"
)

var (name     = flag.String("name", "Tom", "Please input your name:") // 默认值 Tom
    age      = flag.Int("age", 6, "Please input your age:")          // 默认值 6
    hasMoney = flag.Bool("hasMoney", true, "Do you have any money?") // 默认值 true
)

func main() {flag.PrintDefaults() // 打印参数提示信息
    flag.Parse()

    fmt.Printf("name is %s\n", *name)
    fmt.Printf("name is %d\n", *age)
    fmt.Printf("name is %t\n", *hasMoney)
}

// 默认参数
// $ go run main.go
// 输入如下 
/**
    -age int
          Please input your age: (default 6)
    -hasMoney
          Do you have any money? (default true)
    -name string
          Please input your name: (default "Tom")
  name is Tom
  name is 6
  name is true
*/

// 设置参数
// $ go run main.go -name=Jerry -age=8 -hasMoney=false
// 输入如下 
/**
    -age int
          Please input your age: (default 6)
    -hasMoney
          Do you have any money? (default true)
    -name string
          Please input your name: (default "Tom")
  name is Jerry
  name is 8
  name is false
*/

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