Golang Program to Convert String to Object

In Golang program, a string is a data type that contains literals and characters whereas an object is a data type created from classes by keeping similar types of properties together. In this article, we will look at two methods by which we can convert a string to an object in go programming language.

Syntax

func Split(str, sep string) []string

Split() function is used to split a string through a provided separator. This function is present in strings package and it accepts the string to split as an argument along with a separator. The function then returns the final array of strings as a result.

func typeofobject(x interface{})

The typeof() function is used to get the type of any variable. This function is present in reflect package and it takes the variable whose type is to be determined as an argument. The function then returns the type of the variable specified as the result.

func Atoi(s string) (int, error)

Atoi() function is present in strings package and is used to convert a string to integer value. The function accepts the string value as an argument and returns the corresponding integer value after converting it. the function also returns an error variable that contains error if there is some problem in generating the output.

func ValueOf(i interface{}) Value

VslueOf() function is present in reflect package and is used to get the new Value initialized to the concrete value stored in the interface i. To access this function, one needs to imports the reflect package in the program.

Algorithm

• Step 1 − First, we need to import the fmt, json and reflect package.

• Step 2 − Then, create a structure named user and store Name and Age as properties to it.

• Step 3 − Then, create the main() function. Create a variable to string named input and store values to it.

• Step 4 − Next, create an empty variable named user as User type. Further, print the string variable on the screen.

• Step 5 − Now, call the Unmarshal() method present in json package and pass the input variable as byte array as argument to the function along with the user struct.

• Step 6 − No error will be shown if the conversion process is successful. Print the final result on the screen using fmt.Println().

Example 1: Using Json Package

In this program we will use json package to convert a string to an object.

package main
import (
   "encoding/json"
   "fmt"
   "reflect"
)

type User struct {
   Name string
   Age  int
}

func main() {
   input := `{"Name": "Alice", "Age": 25}`
   var user User
   fmt.Println("The given string is:", input, "and its type is:", reflect.TypeOf(input))
   err := json.Unmarshal([]byte(input), &user)
   if err != nil {
      fmt.Println(err)
      return
   }
   fmt.Println()
   fmt.Printf("The object created from the above string is: %+v\n", user)

}

Output

The given string is: {"Name": "Alice", "Age": 25} and its type is: string

The object created from the above string is: {Name:Alice Age:25}

Example 2: Using Reflect Package

In this example we will write a go language program to convert a string to object using reflect package.

package main
import (
   "fmt"
   "reflect"
   "strconv"
   "strings"
)

// creating user structure
type User struct {
   Name string
   Age  int
}

func main() {
   input := "Name:Alice Age:25"
   fmt.Println("The given string is:", input, "and its type is:", reflect.TypeOf(input))
   values := strings.Split(input, " ")
   user := User{}
   // using for loop to iterate over the string
   for _, value := range values {
      parts := strings.Split(value, ":")
	  if len(parts) != 2 {
	      continue
	   }
	   key, val := parts[0], parts[1]
	   v := reflect.ValueOf(&user).Elem()
	   f := v.FieldByName(key)
	   if !f.IsValid() {
	      continue
	   }
	   if f.Type().Kind() == reflect.Int {
	      age, err := strconv.Atoi(val)
		  if err != nil {
		     continue
		  }
		  f.SetInt(int64(age))
	   } else {
			f.SetString(val)
	   }
   }
   fmt.Printf("The object obtained after converting string to object is: %+v\n", user)
}

Output

The given string is: Name:Alice Age:25 and its type is: string
The object obtained after converting string to object is: {Name:Alice Age:25}

Conclusion

We have successfully compiled and executed a go language program to convert a string to object along with examples. We have used two programs here in the first one we are using json package while in the second one we are using reflect package.