["python"]
Insert line at middle of file with Python?

Is there a way to do this? Say I have a file that's a list of names that goes like this: Alfred Bill Donald How could I insert the third name, "Charlie", at line x (in this case 3), and automatically send all others down one line? I've seen other questions like this, but they didn't get helpful answers. Can it be done, preferably with either a method or a loop?
This is a way of doing the trick. with open("path_to_file", "r") as f: contents = f.readlines() contents.insert(index, value) with open("path_to_file", "w") as f: contents = "".join(contents) f.write(contents) index and value are the line and value of your choice, lines starting from 0.