检查文件是否存在的最佳方法:

if _, err := os.Stat("/path/to/file"); err == nil || os.IsExist(err) {
    // your code here if file exists
}

这是我在Go 1.16中检查文件是否存在的方法

package main

import (
    "errors"
    "fmt"
    "io/fs"
    "os"
)

func main () {
    if _, err:= os.Stat("/path/to/file"); errors.Is(err, fs.ErrNotExist){
        fmt.Print(err.Error())
    } else {
        fmt.Print("file exists")
    }
}

检查一个文件是否不存在，相当于Python的if not os.path.exists(filename):

if _, err := os.Stat("/path/to/whatever"); errors.Is(err, os.ErrNotExist) {
  // path/to/whatever does not exist
}

检查一个文件是否存在，相当于Python的if os.path.exists(filename):

编辑:根据最近的评论

if _, err := os.Stat("/path/to/whatever"); err == nil {
  // path/to/whatever exists

} else if errors.Is(err, os.ErrNotExist) {
  // path/to/whatever does *not* exist

} else {
  // Schrodinger: file may or may not exist. See err for details.

  // Therefore, do *NOT* use !os.IsNotExist(err) to test for file existence


}

答案由Caleb Spare张贴在gonuts邮件列表中。

[...] It's not actually needed very often and [...] using os.Stat is easy enough for the cases where it is required. [...] For instance: if you are going to open the file, there's no reason to check whether it exists first. The file could disappear in between checking and opening, and anyway you'll need to check the os.Open error regardless. So you simply call os.IsNotExist(err) after you try to open the file, and deal with its non-existence there (if that requires special handling). [...] You don't need to check for the paths existing at all (and you shouldn't). os.MkdirAll works whether or not the paths already exist. (Also you need to check the error from that call.) Instead of using os.Create, you should use os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666) . That way you'll get an error if the file already exists. Also this doesn't have a race condition with something else making the file, unlike your version which checks for existence beforehand.

摘自:https://groups.google.com/forum/#!味精rl8ffhr8v4j / golang-nuts / Ayx-BMNdMFo / 4

你应该使用os.Stat()和os.IsNotExist()函数，如下例所示:

func Exists(name string) (bool, error) {
    _, err := os.Stat(name)
    if err == nil {
        return true, nil
    }
    if errors.Is(err, os.ErrNotExist) {
        return false, nil
    }
    return false, err
}

修正了在某些情况下返回true的问题。 edit2:从os.IsNotExist()切换到使用errors.Is()，许多人说这是最佳实践

    _, err := os.Stat(file)
    if err == nil {
        log.Printf("file %s exists", file)
    } else if os.IsNotExist(err) {
        log.Printf("file %s not exists", file)
    } else {
        log.Printf("file %s stat error: %v", file, err)
    }