micropython 如何检查文件是否存在？

如何检查文件是否存在？

方法1：

try:

    f = open(filename, "r")

    # continue with the file.

except OSError:  # open failed

   # handle the file open case

方法2：

import os

def file_or_dir_exists(filename):

    try:

        os.stat(filename)

        return True

    except OSError:

        retrun False

方法3：    

import os

def dir_exists(filename):

    try:

        return (os.stat(filename)[0] & 0x4000) != 0

    except OSError:

        return False

def file_exists(filename):

    try:

        return (os.stat(filename)[0] & 0x4000) == 0

    except OSError:

        return False

方法4： 

# Check if path exists.

# Works for relative and absolute path.

def path_exists(path):

    parent = ""  # parent folder name

    name = path  # name of file/folder

    # Check if file/folder has a parent folder

    index = path.rstrip('/').rfind('/')

    if index >= 0:

        index += 1

        parent = path[:index]

        name = path[index:]

    # Searching with iterator is more efficient if the parent contains lost of files/folders

    # return name in uos.listdir(parent)

    return any((name == x[0]) for x in uos.ilistdir(parent))