filegostandard-library

How to check if a file exists in Go?

Does the Go standard library have a function which checks if a file exists (like Python's os.path.exists).

Is there an idiomatic way to check file existence / non-existence?

Solution

  • To check if a file doesn't exist, equivalent to Python's if not os.path.exists(filename):

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

    To check if a file exists, equivalent to Python's if os.path.exists(filename):

    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


}