I'm creating a utility package for my project.
Many of my string slices need a function to 1. remove duplicates 2. remove empty strings
I know 1 way to do this:1. Add a function for each case which accepts a string slice and returns a string slice
func removeEmpty(s []string) []string {
i := 0 // i points to next available pos
for _, v := range s {
if v != "" {
s[i] = v
i++
}
}
return s[:i]
}
func dedup(s []string) []string {
i := 0 // i points to next available pos
mp := map[string]bool{}
for _, v := range s {
if _, ok := mp[v]; !ok {
s[i] = v
mp[v] = true
i++
}
}
return s[:i]
}
when I apply these 2 functions to my slice, I can do:
mySlice := string[]{}
mySlice = dedup(removeEmpty(mySlice))
I want to make it somthing like:
mySlice = mySlice.dedup().removeEmpty()
or
mySlice.dedup().removeEmpty()
Maybe I can add custom method to slice[] ?
I tried writing it
func (s []string) removeEmpty() {
}
I'm getting complie error.
You can't define methods on []string, but you can define your own type based on []string and define methods on that:
type myStringSlice []string
func (s myStringSlice) removeEmpty() myStringSlice {
i := 0 // i points to next available pos
for _, v := range s {
if v != "" {
s[i] = v
i++
}
}
return s[:i]
}
func (s myStringSlice) dedup() myStringSlice {
i := 0 // i points to next available pos
mp := map[string]bool{}
for _, v := range s {
if _, ok := mp[v]; !ok {
s[i] = v
mp[v] = true
i++
}
}
return s[:i]
}
As mentioned in the documentation:
You can only declare a method with a receiver whose type is defined in the same package as the method. You cannot declare a method with a receiver whose type is defined in another package.
So you have to declare a type on []string and then declare the method on your own type.