How to make it so that when saving a new frame, the _ character is added to the file?

Question

Python

I don't know how to explain well, but I hope you get it. I have a program. She divides the video into frames. I need to add _ to the title every time a frame is taken. Something like this:
1st frame - kadr_
2nd frame - kadr__
3rd frame - kadr___
And so on.

Code:

issue resolved

Answer 1

fileName = 'kadr'
frameNumber = 23
fileName += "_"*frameNumber

print(fileName)

cadr_____________________

cv2.imwrite(f"frames/{s}/kadr%.png" % ("_"*i), frame)