Variadic functions in Go

The last parameter can take any number of arguments, arriving as a slice.

func total(label string, values ...int) string {
    sum := 0
    for _, value := range values {
        sum += value
    }
    return fmt.Sprintf("%s=%d over %d values", label, sum, len(values))
}

func callers() []string {
    scores := []int{3, 2, 1}
    return []string{
        total("inline", 1, 2, 3),
        total("spread", scores...),
        total("empty"),
    }
}

How it works

1. Inside the function it is an ordinary slice.
2. slice... spreads an existing slice into the call.
3. Passing none gives a nil slice, which ranges fine.

Keywords and builtins used here

• for
• func
• int
• len
• range
• return
• string

The run, in numbers

Lines

16

Characters to type

316

Tokens

95

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 63 seconds.

Type this snippet

Step 2 of 6 in Functions, step 11 of 30 in Language basics.

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