I'm using a package and instead of returning a string, it returns a economy.ClassId You can see here
I want to pass the economy.ClassId which is just a string of numbers like "531569319" to a function that takes a string not a economy.ClassId so is there a way to convert this type to a string or no. Thanks.
I know you could like strconv.FormatUint() but what would I use for a custom type.
ClassId is declared as type ClassId uint64, so although a ClassId isn't exactly the same as a uint64, they have the same underlying type, and you can therefore convert from one to the other. To convert a value x to type T (when permitted), you write T(x). So, in your case:
funcThatTakesAString(strconv.FormatUint(uint64(classId), 10))
Another approach that is perhaps more idiomatic is to use fmt.Sprintf using Go's format string specification.
Two examples...
The following converts the classId into a string base 10 number:
classIDStr := fmt.Sprintf("%d", classId)
The following converts it into a string hexadecimal number, with a-f digits in lower case:
classIDHex := fmt.Sprintf("%x", classId)
more generally you could implement the stringer interface on your type https://golang.org/pkg/fmt/#Stringer
func (c ClassId) String() string {
return strconv.FormatUint(uint64(c),10)
}
and use that otherFunc(classId.String())
http://play.golang.org/p/cgdQZNR8GF
PS: also acronymes (ID) should be all capitals