How are golang variable parameters implemented?

There are no variadic parameters in the traditional sense in the Go language, but they can be implemented through built-in... syntactic sugar: function variadic parameters: using..., the parameters are collected into a slice. Method varargs: Similar to functions, but the varargs list must be passed as the last argument. Variable parameters are implemented through... syntax sugar, which can be used in scenarios such as calculating the sum of a variable number of integers, constructing a variable-length string array, etc. Understanding variadic arguments is critical to writing flexible, scalable Go code.

Go language variable parameters: revealing the underlying implementation

Introduction

There is no variable parameter function in the traditional sense in the Go language , but we can do it in other ways. This article will delve into the implementation principles of variable parameters in Go and demonstrate its usage through practical cases.

Function variable parameters

The Go language implements function variable parameters through the built-in ... syntax sugar syntax. When ... is present in a function signature, it means that the function accepts an undetermined number of parameters. These parameters are collected into a slice, which can be indexed using [].

func Sum(args ...int) int {
    sum := 0
    for _, v := range args {
        sum += v
    }
    return sum
}

Method variable parameters

For methods, the implementation of variable parameters is slightly different. Similar to functions, method variable parameters are also implemented through ... syntactic sugar. However, in method calls, the variadic argument list must be passed as the last argument.

type Calculator struct {
    result int
}

func (c *Calculator) Add(args ...int) {
    for _, v := range args {
        c.result += v
    }
}

Practical case

Example 1: Calculate the sum of a variable number of integers

package main

import "fmt"

func main() {
    res := Sum(1, 2, 3, 4, 5)
    fmt.Println(res) // 输出：15
}

func Sum(args ...int) int {
    sum := 0
    for _, v := range args {
        sum += v
    }
    return sum
}

Example 2: Construct a variable-length character String array

package main

import "fmt"

func main() {
    names := []string{"John", "Mary", "Bob", "Alice"}
    fmt.Println(NewStringArray(names...)) // 输出：[John Mary Bob Alice]
}

func NewStringArray(args ...string) []string {
    return args
}

Conclusion

Variable parameters are a powerful and flexible feature in the Go language, which can be implemented through ... syntax sugar. Understanding variadic arguments is important for writing flexible and scalable Go code.

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