Python 说它找不到我要重命名的文件，即使它可以读取文件名

Question

Im tryin to append a short string to every '.png' file. But when I run it, it says cannot find the file. But I know it's there and I can see it in the folder.

Is there anything I need to do?

Here is my script:

import os

for file in os.listdir("./pics"):
    if file.endswith(".png"):
        newFileName = "{0}_{2}{1}".format(*os.path.splitext(file) + ("z4",))
        os.rename(file, newFileName)

Here is the error message I get...02.png is the first file in the folder:

fileNotFoundError: [WinError 2] The system cannot find the file specified: '02.png' -> '02_z4.png'

It's odd though because it gets the filename, in this case, 02.png . So if it can read the file name, why can't it find it?

Thanks!

Answer 1

I thought my comment might be enough, but for clarity I'll provide a short answer.

02.png doesn't exist relative to your working directory. You need to specify the path to the file for os.rename so you need to include the directory.

import os

for file in os.listdir("./pics"):
    if file.endswith(".png"):
        newFileName = "/pics/{0}_{2}{1}".format(*os.path.splitext(file) + ("z4",)) # Notice the ./pics
        os.rename(os.path.join('pics', file), newFileName)

Answer 2

The name returned from os.listdir() gives the filename, not the full path. So you need to rename pics/02.png to pics/02_zf.png. Right now you don't include the directory name.