哪个扫描用于读取字符串的浮点数？

This seems almost right but it chokes on the newline. What's the best way to do this?

package main

import (
    "fmt"
    "strings"
)

func main() {
    var z float64
    var a []float64
    // 
 gives an error for Fscanf
    s := "3.25 -12.6 33.7 
 3.47"
    in := strings.NewReader(s)
    for {
        n, err := fmt.Fscanf(in, "%f", &z)
        fmt.Println("n", n)
        if err != nil {
            break
        }
        a = append(a, z)
    }
    fmt.Println(a)
}

Output:

n 1
n 1
n 1
n 0
[3.25 -12.6 33.7]

Update:

See the answer from @Atom below. I found another way which is to break if the error is EOF, and otherwise just ignore it. It's just a hack, I know, but I control the source.

    _, err := fmt.Fscanf(in, "%f", &z)
    if err == os.EOF { break }
    if err != nil { continue }

If you are parsing floats only, you can use fmt.Fscan(r io.Reader, a ...interface{}) instead of fmt.Fscanf(r io.Reader, format string, a ...interface{}):

var z float64
...
n, err := fmt.Fscan(in, &z)

The difference between fmt.Fscan and fmt.Fscanf is that in the case of fmt.Fscan newlines count as space. The latter function (with a format string) does not treat newlines as spaces and requires newlines in the input to match newlines in the format string.

The functions with a format string give more control over the form of input, such as when you need to scan %5f or %10s. In this case, if the input contains newlines and it implements the interface io.RuneScanner you can use the method ReadRune to peek the next character and optionally unread it with UnreadRune if it isn't a space or a newline.

If your input is just a bunch of lines with floats separated by white space on each line, it might be easier to just read one line at a time from the file, run Sscanf on that line (assuming the number of floats on each line is fixed). But here's something that works in your example---there may be a way to make it more efficient.

package main

import (
    "fmt"
    "strings"
)

func main() {
    var z float64
    var a []float64
    // 
 gives an error for Fscanf
    s := "3.25 -12.6 33.7 
 3.47"
    for _, line := range strings.Split(s, "
") {
        in := strings.NewReader(line)
        for {
            n, err := fmt.Fscanf(in, "%f", &z)
            fmt.Println("n", n)
            if err != nil {
                fmt.Printf("ERROR: %v
", err)
                break
            }
            a = append(a, z)
        }
    }
    fmt.Println(a)
}