What is the difference between []string and ...string in golang?

Question

In the Go language,

[]string is a string array

and we also use ...string as a parameter.

What is the difference?

Function definition:

func f(args ...string) {} 

Can I call this function like below?

args := []string{"a", "b"}  f(args) 

Answer 1

[]string is a string array

Technically it's a slice that references an underlying array

and we also use ...string as a parameter.

What is the difference?

With respect to the structure, nothing really. The data type resulting from both syntax is the same.

The ... parameter syntax makes a variadic parameter. It will accept zero or more string arguments, and reference them as a slice.

With respect to calling f, you can pass a slice of strings into the variadic parameter with the following syntax:

func f(args ...string) {     fmt.Println(len(args)) }   args := []string{"a", "b"}  f(args...) 

This syntax is available for either the slice built using the literal syntax, or the slice representing the variadic parameter (since there's really no difference between them).

http://play.golang.org/p/QWmzgIWpF8

Answer 2

Both create an array of strings, but the difference is in how it is called.

func f(args ...string) {  } // Would be called like this:  f("foo","bar","baz"); 

This allows you to accept a variable number of arguments (all of the same type)

A great example of this is fmt.Print and friends, which can accept as few or as many arugments as you want.