Go隨機數實例

Go的math/rand包提供僞隨機數生成。例如，rand.Intn返回一個隨機int n，0 <= n <100。

rand.Float64返回一個float64 f，0.0 <= f <1.0。這可以用於生成其他範圍內的隨機浮點，例如5.0 <= f'<10.0。

可參考示例中的代碼 -

所有的示例代碼，都放在 F:\worksp\golang 目錄下。安裝Go編程環境請參考：http://www.yiibai.com/go/go\_environment.html

json.go的完整代碼如下所示 -

package main

import "fmt"
import "time"

func main() {
    p := fmt.Println

    // Here's a basic example of formatting a time
    // according to RFC3339, using the corresponding layout
    // constant.
    t := time.Now()
    p(t.Format(time.RFC3339))

    // Time parsing uses the same layout values as `Format`.
    t1, e := time.Parse(
        time.RFC3339,
        "2012-11-01T22:08:41+00:00")
    p(t1)

    // `Format` and `Parse` use example-based layouts. Usually
    // you'll use a constant from `time` for these layouts, but
    // you can also supply custom layouts. Layouts must use the
    // reference time `Mon Jan 2 15:04:05 MST 2006` to show the
    // pattern with which to format/parse a given time/string.
    // The example time must be exactly as shown: the year 2006,
    // 15 for the hour, Monday for the day of the week, etc.
    p(t.Format("3:04PM"))
    p(t.Format("Mon Jan _2 15:04:05 2006"))
    p(t.Format("2006-01-02T15:04:05.999999-07:00"))
    form := "3 04 PM"
    t2, e := time.Parse(form, "8 41 PM")
    p(t2)

    // For purely numeric representations you can also
    // use standard string formatting with the extracted
    // components of the time value.
    fmt.Printf("%d-%02d-%02dT%02d:%02d:%02d-00:00\n",
        t.Year(), t.Month(), t.Day(),
        t.Hour(), t.Minute(), t.Second())

    // `Parse` will return an error on malformed input
    // explaining the parsing problem.
    ansic := "Mon Jan _2 15:04:05 2006"
    _, e = time.Parse(ansic, "8:41PM")
    p(e)
}

執行上面代碼，將得到以下輸出結果 -

F:\worksp\golang>go run random-numbers.go
81,87
0.6645600532184904
7.1885709359349015,7.123187485356329
54,68
5,87
5,87