Golang : fmt.Println prints out empty data from struct
Problem :
Your code compiled successfully and there is no error indicator whatsoever. However, during runtime, the fmt.Println function prints out empty data that you expected from a struct that suppose to have unmarshaled JSON data. What's going on?
For example :
package main
import "fmt"
import "encoding/json"
func main() {
var v = []byte(`[
{
"name": "D***",
"email": "D***@gmail.com"
"gender": "Male",
"age": 27,
}
{
"name": "A***",
"email": "a@a.com"
"gender": "Female",
"age": 31,
}
]`)
type Person struct {
name string
email string
gender string
age int
}
var people []Person
err := json.Unmarshal(v, &people)
if err != nil {
}
fmt.Println(people)
}
http://play.golang.org/p/gHqiCLk-rV
will compile just fine, but will print out empty data.
Solution :
Use JSON Linter to validate the JSON data. ( http://jsonlint.com/ )
The variables names inside the Person struct starts with small cap, this means those variables are
private
type and cannot be displayed. Thus, this explains why the fmt.Println function prints out empty data. To fix the problem, change the variables names to start with big cap to make thempublic
type. See the fixed code at http://play.golang.org/p/xLfz_aofCQ
By Adam Ng
IF you gain some knowledge or the information here solved your programming problem. Please consider donating to the less fortunate or some charities that you like. Apart from donation, planting trees, volunteering or reducing your carbon footprint will be great too.
Advertisement
Tutorials
+12.3k Golang : How to check if a string starts or ends with certain characters or words?
+8.1k Golang : Multiplexer with net/http and map
+13k Golang : List objects in AWS S3 bucket
+11.6k Golang : Concurrency and goroutine example
+6.5k Golang : Convert an executable file into []byte example
+5k Google : Block or disable caching of your website content
+5.2k PHP : See installed compiled-in-modules
+11.9k Golang : Convert decimal number(integer) to IPv4 address
+37.5k Upload multiple files with Go
+12.7k Android Studio : Highlight ImageButton when pressed on example
+11k Golang : Replace a parameter's value inside a configuration file example
+12.2k Golang : List running EC2 instances and descriptions