How to expand variables with fmt.Println()

Question

I can't expand variables with fmt.Println().

package main
import "fmt"
func main(){
  old := 20
  fmt.Println("I'm %g years old.",old)
}

result =>

I'm %g years old.
20

What do you mean by 'export'? Please show us a full example of what you are trying to achieve and where it fails. — nemo, Apr 17 '17 at 04:34
2) Println doesn't format, that's what Printf and family are for. — , Apr 17 '17 at 04:35

score 5 · Accepted Answer · answered Apr 17 '17 at 04:52

5

Use Printf not Println. Use %d for old which is type int. Add a newline.

For example,

package main

import "fmt"

func main() {
    old := 20
    fmt.Printf("I'm %d years old.\n", old)
}

Output:

I'm 20 years old.

answered Apr 17 '17 at 04:52

peterSO

score 1 · Answer 2 · answered Apr 17 '17 at 04:52

1

As the documentation for fmt.Println states, this function does not support format specifiers. Use fmt.Printf instead.

answered Apr 17 '17 at 04:52

nemo

2 Answers2