golang fmt格式化字符串%v,%T

[AlexZ33]

T常用的格式化字符串有：

%v the value in a default format
when printing structs, the plus flag (%+v) adds field names
%#v a Go-syntax representation of the value
%T a Go-syntax representation of the type of the value

不同类型默认的%v 如下:

bool: %t
int, int8 etc.: %d
uint, uint8 etc.: %d, %#x if printed with %#v
float32, complex64, etc: %g
string: %s
chan: %p
pointer: %p

对于interface{}, %v会打印实际类型的值。
举例说明如下:

package main

import(
    "fmt"
)

type Power struct {
         age int
         high int
         name string
}

func main() {
       var i Power = Power{age:10, high:178, name: "NewMan"}
       fmt.Printf("type:%T\n", i)
        fmt.Printf("value:%v\n", i)
        fmt.Printf("value+:%+v\n", i)
        fmt.Printf("value#:%#v\n", i)
 
 
        fmt.Println("========interface========")
        var interf interface{} = i
        fmt.Printf("%v\n", interf)
        fmt.Println(interf)
}

// type:main.Power
// value:{10 178 NewMan}
// value+:{age:10 hight:178 name:NewMan}
// value#:main.Power{age:10, hight:178, name:"NewMan"}
// ========interface========
// {10 178 NewMan}
// {10 178 NewMan}