使用Golang对文件名中的数字进行字符串排序

AMA1.txtAMA2.txt

files=[]
for file in os.listdir(someDir):

    if file.endswith(".txt"):
     files.append(file) 

convert = lambda text: int(text) if text.isdigit() else text 
alphanum_key = lambda key: [ convert(c) for c in re.split('([0-9]+)',key) ]

files.sort( key=alphanum_key )

for i in files:
    print (i)

I got so far, but missing the sorting :

func main() {
    dirname := "someDir"
    d, err := os.Open(dirname)

    if err != nil {
        fmt.Println(err)
    }

    defer d.Close()

    fi, err := d.Readdir(-1)

    if err != nil {
        fmt.Println(err)
    }

    for _, fi := range fi {
        if fi.Mode().IsRegular() {
            fmt.Println(fi.Name())
        }
    }
}