Golang flag
flag 是 go 標(biāo)準(zhǔn)庫提供的解析命令行參數(shù)的包亡笑。
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flag use style
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flag.Type(name, defvalue, usage)其中 Type: [String, Int, Bool ...], 并返回一個相應(yīng)類型的指針踱蛀。 -
將 flag 綁定到一個變量上 :
flag.TypeVar(&flagvar, name, defvalue, usage)其中 Type: [String, Int, Bool ...]
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Custom flag
只要實現(xiàn)
flag.Valueinterface:type Value interface { String() string Set(string) error }以
flag.Var(&flagvar, name, usage)方式定義此 flag -
Example
package main import ( "flag" "fmt" "strconv" ) const APP_VERSION = "0.1" type percentage float32 func (p *percentage) Set(s string) error { v, err := strconv.ParseFloat(s, 32) *p = percentage(v) return err } func (p *percentage) String() string { return fmt.Sprintf("%f", *p) } func main() { // *T namePtr := flag.String("name", "hl", "user`s name") agePtr := flag.Int("age", 22, "user`s age") vipPtr := flag.Bool("vip", true, "is a vip user") var email string flag.StringVar(&email, "email", "hlGopen@doingsbook.com", "user`s email") // p := &email // fmt.Println(p) // fmt.Println(*p) var pop percentage flag.Var(&pop, "pop", "popularity") flag.Parse() // Scan the arguments list others := flag.Args() if *vipPtr { fmt.Println("Version:", APP_VERSION) } fmt.Println("name: ", *namePtr) fmt.Println("age: ", *agePtr) fmt.Println("pop: ", pop) fmt.Println("email: ", email) fmt.Println("others: ", others) }
$ ./command-line-flags Version: 0.1 name: hl age: 22 pop: 0 email: hlGopen@doingsbook.com others: []$ ./command-line-flags -name golang -age 20 -vip=false -pop 99 簡潔 高并發(fā) 等等 name: golang age: 20 pop: 99 email: hlGopen@doingsbook.com others: [簡潔 高并發(fā) 等等]$ ./command-line-flags -h Usage of command-line-flags: -age=22: user`s age -email="hlGopen@doingsbook.com": user`s email -name="hl": user`s name -pop=0.000000: popularity -vip=true: is a vip user
