using curly braces in filepaths

Trying to create animation effect by for looping images on a specific file path and found that:
THIS WORKS:

img=pygame.image.load(f'/img/{self.char_type}/walk/0.png') 

note 0.png but this DOES NOT:

img=pygame.image.load(f'/img/{self.char_type}/walk/{i}.png')

where i is from the simple FOR loop.

All FAQ posts read so far suggest swapping / for , using f and r, using // or \ and even importing pathlib but all these seem to fail – so anyone got a sure fire method please?

>Solution :

Make a string first and pass it to the loader.

for i in range(11):
    srt = f'/img/{self.char_type}/walk/{i}.png'
    img=pygame.image.load(srt)