Fast scanning of a large UTF-8 string

问题:

I have a string of about 8000000 UTF-8 characters. Scanning it via fmt.Scanf() takes about 10 seconds, how can I do it faster? I have a Go wrapper for C scanf() function that was written by my teacher as a workaround for some bugs in Go's fmt.Scanf(), it works in 1-2 seconds, but I don't like using side packages for such simple tasks. Could you suggest some faster way of reading strings in pure Go?

回答1:

Found the solution. bufio works much faster (as it's buffered, and fmt's functions are not, and it doesn't parse anything):

reader := bufio.NewReader(os.Stdin)
str, _ := reader.ReadString('\n')   // Like fmt.Scanf("%s", &str), but faster
var x, y rune
fmt.Fscanf(reader, "%c %c", &x, &y) // I need to read something else
                                    // (see comments for the question)
                                    // It's easy, as I can use fmt.Fscanf

...even faster that that C scanf() wrapper.