When I run a python program and then go back and want to repair the errors I made, I can't do that. Is there a way to avoid rewriting all?
Are you writing the program in the shell or something? A python program is really nothing more than a text file so this should be fairly easy to get right. I just open the shell. go to file, new and a built in python editor pops up. Then I type the program and save as example.py and I'm good to go. you could write a python program with notepad as long as you were careful with indentation. Then you would just need to save the .txt as a .py and you're good to go.
If you want to re open the same file go to file, open and navigate to where ever you saved it in the first place.