golangmapstructure数组

Introduction

Mapstructure is a Golang package that provides a way to bind data from a map to a Go struct. Mapstructure can be used to decode data from multiple sources such as JSON, YAML, and HCL. It allows for easy conversion of data structured as maps to Go structs. In this article, we will focus on using Mapstructure to decode arrays in Go structs.

Working with Arrays in Golang

Arrays in Golang are a collection of values of the same type. They can be defined using the following syntax:

var arr [5]int

The above code creates an integer array of length 5. Arrays in Golang are fixed-length and can’t be resized once created. However, slices( [] ) can be resized. Slices are a combination of pointer, length, and capacity. We can have a slice of various datatypes like int, float, etc. defined using the following syntax:

var s []int

Now that we have a basic understanding of arrays and slices in Golang, let’s see how we can use Mapstructure to decode arrays in our Go structs.

Decoding Arrays Using Mapstructure

In order to decode arrays in Go structs, we need to define our struct with the expected array type. For instance, if we have an array of integers in our data source, we can define our Go struct as follows:

type IntArr struct {

arr []int `mapstructure:"arr"`

}

The `mapstructure` tag helps Mapstructure to understand which field in the struct maps to which attribute in the source data. Once the struct is defined, we can use Mapstructure’s `Decode` function to decode the array data into our struct:

var mapData map[string]interface{}

// load your map data

var intArr IntArr

decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{

    TagName: "mapstructure",

    Result: &intArr,

  })

if err != nil {

    // handle error

}

if err := decoder.Decode(&mapData); err != nil {

    // handle error

}

The above code will decode the array from the source map into our Go struct. Mapstructure can handle decoding of various datatypes from a map to a Go struct, such as refer (struct), slice ([]string, []int), point (*string, *int), etc.

Conclusion

Working with data in Go can be challenging, especially when decoding data from various sources. Mapstructure provides an easy way to decode data from a map to a Go struct, and with the ability to decode arrays, it makes handling data from sources such as JSON, YAML, and HCL much more straightforward. By understanding the basics of arrays and slices in Golang, we can use Mapstructure to decode array data into our Go structs and create robust applications that handle complex data formats.