Go语言圣经-函数多返回值1.在Go中，一个函数可以返回多个值2.许多标准库中的函数返回2个值，一个是期望得到的返回值，另一个是函数出错时的错误信息3.如果一个函数将所有的返回值都显示的变量名，那么该函数的return语句可以省略操作数。这称之为bare return。
import (
"fmt"
"golang.org/x/net/html"
"net/http"
"os"
"strings"
)
/
练习 5.5： 实现countWordsAndImages。（参考练习4.9如何分词）
/
func main() {
words,images,_ := CountWordsAndImages(os.Args[1])
fmt.Printf("文字：%d,图片：%d n",words,images)
}
// CountWordsAndImages does an HTTP GET request for the HTML
// document url and returns the number of words and images in it.
func CountWordsAndImages(url string) (words,images int,err error) {
resp,err := http.Get(url)
if err != nil {
return
}
doc,err := html.Parse(resp.Body)
resp.Body.Close()
if err != nil {
err = fmt.Errorf("parsing HTML: %s",err)
return
}
words,images = countWordsAndImages(doc)
//bare return
return
}
func countWordsAndImages(n *html.Node) (words,images int) {
texts,images := visit3(nil,n)
for _,v := range texts {
v = strings.Trim(strings.TrimSpace(v),"rn")
if v == "" {
continue
}
words += strings.Count(v,"")
}
//bare return
return
}
//递归循环html
func visit3(texts []string,imgs int,n *html.Node) ([]string,int) {
//文本
if n.Type == html.TextNode {
texts = append(texts,n.Data)
}
//图片
if n.Type == html.ElementNode && (n.Data == "img") {
imgs++
}
for c := n.FirstChild; c != nil; c = c.NextSibling {
if c.Data == "script" || c.Data == "style" {
continue
}
texts,imgs = visit3(texts,imgs,c)
}
//多返回值
return texts,imgs
}
