Variadic Functions: Flexible Argument Handling

Snippet

Variadic Functions: Flexible Argument Handling

Variadic functions accept any number of arguments of the same type. The ... syntax before the type parameter makes a function variadic. Inside the function, the variable is received as a slice. You can pass individual arguments or unpack a slice using the ... operator. This pattern is useful for logging, formatting, and utility functions.

snippet.go
go
package main
 
import "fmt"
 
func sum(numbers ...int) int {
    total := 0
    for _, n := range numbers {
        total += n
    }
    return total
}
 
func greet(greeting string, names ...string) {
    for _, name := range names {
        fmt.Printf("%s, %s!\n", greeting, name)
    }
}
 
func combine(base string, parts ...string) string {
    result := base
    for _, part := range parts {
        result += "|" + part
    }
    return result
}
 
func main() {
    fmt.Println("Sum:", sum(1, 2, 3, 4, 5))
    fmt.Println("Sum of no numbers:", sum())
 
    greet("Hello", "Alice", "Bob", "Charlie")
 
    fmt.Println("Combined:", combine("Start", "A", "B", "C"))
 
    nums := []int{10, 20, 30}
    fmt.Println("Slice sum:", sum(nums...))
}

Breakdown

func sum(numbers ...int) int

Declares a variadic function accepting zero or more int arguments

for _, n := range numbers

The variadic parameter is a slice inside the function, so range works on it

greet("Hello", "Alice", "Bob")

Can pass any number of string arguments after the required first parameter

nums := []int{10, 20, 30}; sum(nums...)

The ... unpacks a slice into individual arguments for the variadic function

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Variadic Functions: Flexible Argument Handling

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