Error embedding "\n" into a string literal

Question

I need to decode a JSON string which has "\n" in it:

[
    {"Name":"Neo", "Message":"Hi\n:Hello everyone"},
    {"Name":"Sam","Messsage":"Hello\nEveery\nOne"}
]

I use the Golang code below:

package main

import (
    "encoding/json"
    "fmt"
)

type Person struct {
    Messages  []string     `json:"Name,omitempty"`
}

func main() {
s := "[{\"Name\":\"Neo\", \"Message\":\"Hi\n:Hello everyone\"},   {\"Name\":\"Sam\",\"Messsage\":\"Hello\nEveery\nOne\"}]"
var pro Person
err := json.Unmarshal([]byte(s), &pro)
if err == nil {
fmt.Printf("%+v\n", pro)
} else {
fmt.Println(err)
fmt.Printf("%+v\n", err)
}
}

But I get the error:

ERROR invalid character '\n' in string literal

The problem you have is how you define the example string. In your example you have to double escape it like so: "[{\"Message\": \"Hi\\n:Hello\"}]. But you should really use this syntax `[{"Message": "Hi\n:Hello"}]` for readability, as suggested in the play link in earlier comment. — baloo
– baloo, Commented Aug 16, 2016 at 14:58

user5728991 · Accepted Answer · 2016-08-16 16:06:52Z

14

There are a few of issues here. The first is that newline is not allowed in a JSON string. Use the two bytes \n to specify a newline, not an actual newline. If you use an interpreted string literal, then the \ must be quoted with a \. Example:

"Hello\\nWorld"

No quoting is required in a raw string literal:

`Hello\nWorld`

The next issue is that JSON value is an array of object values. To handle the array, unmarshal to a slice:

var pro []Person
err := json.Unmarshal([]byte(s), &pro)

To handle the objects, define Person as a struct:

type Person struct {
  Name    string
  Message string
}

working example on the playground.

answered Aug 16, 2016 at 16:06

user5728991

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Comments

score 2 · Accepted Answer · 2016-08-16 17:51:28Z

2

Use backtick, like this working sample code:

package main

import (
    "encoding/json"
    "fmt"
)

type Person struct {
    Name    string `json:"Name"`
    Message string `json:"Message"`
}

func main() {
    s := `
[
    {"Name":"Neo", "Message":"Hi\n:Hello everyone"},
    {"Name":"Sam", "Message":"Hello\nEvery\nOne"}
]   
    `
    var pro []Person
    err := json.Unmarshal([]byte(s), &pro)
    if err != nil {
        fmt.Println(err)
    }
    fmt.Printf("%q\n", pro)
    fmt.Println()
    fmt.Println(pro)

}

output:

[{"Neo" "Hi\n:Hello everyone"} {"Sam" "Hello\nEvery\nOne"}]

[{Neo Hi
:Hello everyone} {Sam Hello
Every
One}]

edited Aug 16, 2016 at 17:51

answered Aug 16, 2016 at 16:06

user6169399

1 Comment

user6169399 Over a year ago

@hardy I hope this helps.

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