Question

I wish there is an efficient way to print out my format.
As I know convert to string may occur performance issue.
Is there any better method?

package main

import "fmt"

type T struct {
  order_no [5]byte
  qty int32
}
func (t T)String() string {
  return fmt.Sprint("order_no=", t.order_no, 
    "qty=", t.qty)
}

func main() {
        v := T{[5]byte{'A','0','0','0','1'}, 100}

    fmt.Println(v)
}    

The output is order_no=[65 48 48 48 49]qty=100
I wish it will be order_no=A0001 qty=100.

BTW, why func (t T)String() string work and func (t *T)String() string can not work.(on goplay)

Answer 1

package main

import "fmt"

type T struct {
    order_no [5]byte
    qty      int32
}

func (t T) String() string {
    return fmt.Sprint(
        "order_no=", string(t.order_no[:]),
        " qty=", t.qty,
    )
}

func main() {
    v := T{[5]byte{'A', '0', '0', '0', '1'}, 100}
    fmt.Println(v)
}

Output:

order_no=A0001 qty=100