insert a tkinter progress bar in a List Comprehensions of Python
If you are concerned about performance, remove the call to self.update(). It will slow your loop down by up to three orders of magnitude. At the very least you should call it only every 1,000 iterations or so.
In a quick test, I can do 10,000 simple calculations that result in 1% of the values being appended to a loop in about .0016 seconds. When I add a call to update in the loop, the time expands to 1.0148 seconds.
You said in a comment you have 80 million rows to iterate over. My same code can process 80 million calculations in 12 seconds, versus over 2 hours when I add in a call to update.
Converting your code to using a list comprehension will have a negligible effect compared to removing or reducing the calls to update.