英文:
How to terminate early in Golang Walk?
问题
如果可能的话，使用Go的filepath.Walk提前返回的惯用方法是什么？
我正在编写一个函数来查找给定名称的嵌套目录。使用filepath.Walk，我无法找到一种在找到第一个匹配项后终止树遍历的方法。
func (*RecursiveFinder) Find(needle string, haystack string) (result string, err error) {
filepath.Walk(haystack, func(path string, fi os.FileInfo, errIn error) (errOut error) {
fmt.Println(path)
if fi.Name() == needle {
fmt.Println("Found " + path)
result = path
return nil
}
return
})
return
}
英文:
What's the idiomatic way, if possible, of having Go's filepath.Walk return early?
I'm writing a function to find a nested directory of a given name. Using filepath.Walk I can't see a way of terminating the tree-walking as soon as I find the first match.
func (*RecursiveFinder) Find(needle string, haystack string) (result string, err error) {
filepath.Walk(haystack, func(path string, fi os.FileInfo, errIn error) (errOut error) {
fmt.Println(path)
if fi.Name() == needle {
fmt.Println("Found " + path)
result = path
return nil
}
return
})
return
}
答案1
得分: 17
你应该从walkfunc中返回一个错误。为了确保没有返回真正的错误，你可以使用一个已知的错误，比如io.EOF。
func Find(needle string, haystack string) (result string, err error) {
err = filepath.Walk(haystack,
filepath.WalkFunc(func(path string, fi os.FileInfo, errIn error) error {
fmt.Println(path)
if fi.Name() == needle {
fmt.Println("Found " + path)
result = path
return io.EOF
}
return nil
}))
if err == io.EOF {
err = nil
}
return
}
英文:
You should return an error from your walkfunc. To make sure no real error has been returned, you can just use a known error, like io.EOF.
func Find(needle string, haystack string) (result string, err error) {
err = filepath.Walk(haystack,
filepath.WalkFunc(func(path string, fi os.FileInfo, errIn error) error {
fmt.Println(path)
if fi.Name() == needle {
fmt.Println("Found " + path)
result = path
return io.EOF
}
return nil
}))
if err == io.EOF {
err = nil
}
return
}
答案2
得分: 0
你可以使用errors.New来定义自己的错误：
import (
"errors"
"os"
"path/filepath"
)
var stopWalk = errors.New("停止遍历")
func find(name, root string) (string, error) {
var spath string
e := filepath.Walk(root, func (path string, info os.FileInfo, e error) error {
if info.Name() == name {
spath = path
return stopWalk
}
return e
})
if e == stopWalk {
return spath, nil
}
return "", e
}
或者你可以使用filepath.Glob：
import "path/filepath"
func find(pattern string) (string, error) {
paths, e := filepath.Glob(pattern)
if paths == nil { return "", e }
return paths[0], nil
}
英文:
You can use errors.New to define your own error:
import (
"errors"
"os"
"path/filepath"
)
var stopWalk = errors.New("stop walking")
func find(name, root string) (string, error) {
var spath string
e := filepath.Walk(root, func (path string, info os.FileInfo, e error) error {
if info.Name() == name {
spath = path
return stopWalk
}
return e
})
if e == stopWalk {
return spath, nil
}
return "", e
}
Or you can use filepath.Glob:
import "path/filepath"
func find(pattern string) (string, error) {
paths, e := filepath.Glob(pattern)
if paths == nil { return "", e }
return paths[0], nil
}
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