Decode large stream JSON

Question

I have a massive JSON array stored in a file (\"file.json\") I need to iterate through the array and do some operation on each element.

err = json.Unmarshal(         


        

Answer 1

So, as commenters suggested, you could use the streaming API of "encoding/json" for reading one string at a time:

r := ... // get some io.Reader (e.g. open the big array file)
d := json.NewDecoder(r)
// read "["
d.Token()
// read strings one by one
for d.More() {
    s, _ := d.Token()
    // do something with s which is the newly read string
    fmt.Printf("read %q\n", s)
}
// (optionally) read "]"
d.Token()

Note that for simplicity I've left error handling out which needs to be implemented.