How to Parse JSON Arrays in Go using the `encoding/json` Package?

Parsing JSON Arrays in Go Using the JSON Package

Question

How can I parse a string that represents a JSON array in Go using the encoding/json package?

type JsonType struct {
    Array []string
}

func main() {
    dataJson := `["1","2","3"]`
    arr := JsonType{}
    unmarshaled := json.Unmarshal([]byte(dataJson), &arr.Array)
    log.Printf("Unmarshaled: %v", unmarshaled)
}

Answer

The provided code returns the error value from Unmarshal. To correctly parse the JSON array, use the following code:

err := json.Unmarshal([]byte(dataJson), &arr)

Additionally, you can simplify the code by using a slice instead of a custom struct:

package main

import (
    "encoding/json"
    "fmt"
)

func main() {
    dataJson := `["1","2","3"]`
    var arr []string
    err := json.Unmarshal([]byte(dataJson), &arr)
    fmt.Println(err)
    fmt.Println(arr)
}

This code will output:

<nil>
[1 2 3]

Background

Passing a pointer to Unmarshal enables the function to reduce or eliminate memory allocations. Additionally, in a processing context, the caller may reuse the same value repeatedly, further saving allocations.

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