go / golang difference between := vs =

:= is for declaration + assignment, and = is for assignment only

For the golang documentation:

Inside a function, the := short assignment statement can be used in place of a var declaration with implicit type.

Outside a function, every construct begins with a keyword (var, func, and so on) and the := construct is not available.

In the below example:

the usage of both := and  = operator can be seen.

func Reverse(s string) string {

 r := []rune(s)

 for i,j := 0,len(r)-1 ; i < len(r)/2 ; i,j=i+1,j-1 {

  r[i],r[j] = r[j],r[i]

 }

 return string(r)



}