如何调整代码以新的数字开头？

Question

import os
src = "/home/user/Desktop/images/"
ext = ".jpg"
for i,filename in enumerate(os.listdir(src)):
    # print(i,filename)

    if filename.endswith(ext):
        os.rename(src + filename, src + str(i) + ext)
        print(filename, src + str(i) + ext)
    else :
        os.remove(src + filename)

this code will rename all the images in a folder starting with 0.jpg,1.jpg etc... and remove none jpg but what if i already had some images in that folder, let's say i had images 0.jpg, 1.jpg, 2.jpg, then i added a few others called im5.jpg and someImage.jpg.

What i want to do is adjust the code to read the value of the last image number, in this case 2 and start counting from 3 . In other words i'll ignore the already labeled images and proceed with the new ones counting from 3.

Answer 1

Terse and semi-tested version:

import os
import glob
offset = sorted(int(os.path.splitext(os.path.basename(filename))[0]) 
                for filename in glob.glob(os.path.join(src, '*' + ext)))[-1] + 1

for i, filename in enumerate(os.listdir(src), start=offset):
    ...

Provided all *.jpg files consist of a only a number before their extension. Otherwise you will get a ValueError .

And if there happens to be a gap in the numbering, that gap will not be filled with new files. Eg, 1.jpg, 2.jpg, 3.jpg, 123.jpg will continue with 124.jpg (which is safer anyway).

---

If you need to filter out filenames such as im5.jpg or someImage.jpg, you could add an if-clause to the list comprehension, with a regular expression:

import os
import glob
import re
offset = sorted(int(os.path.splitext(os.path.basename(filename))[0]) 
                for filename in glob.glob(os.path.join(src, '*' + ext))
                if re.search('\d+' + ext, filename))[-1] + 1

Of course, by now the three lines are pretty unreadable, and may not win the code beauty contest.