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
+4.5k Javascript : Shuffle or randomize array example
+22.4k Golang : Use regular expression to validate domain name
+14k Golang : Get digits from integer before and after given position example
+15.4k Golang : How to implement two-factor authentication?
+12.4k Golang : Query string with space symbol %20 in between
+14.1k Golang : Validate hostname
+16.4k Convert JSON to CSV in Golang
+6.8k Golang : Get today's weekday name and calculate target day distance example
+8.7k Golang : Ordinal and Ordinalize a given number to the English ordinal numeral
+5.3k Golang : How to get capacity of a slice or array?
+4.2k Golang : Get FX sentiment from website example
+7.2k How to show different content from website server when AdBlock is detected?