How correct save information in file python

Question

I have a problem with saving and reading a file in a kivy application. For some reason new spaces appear after saving the file.

I think the point is that “text at the end with \n” is read as one line, but is entered into the field as two lines, and then saved to a file as 2 lines, and this becomes a problem.

I signed where in the code the work with the file occurs. Please help me because I don't understand it myself.

test.py '''

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen


class Screeen(Screen):
    None
class Manager(ScreenManager):
    None



class appApp(App):


    def on_start(self):  # When the application starts, the file is read and the data is entered into the input fields
        with open("settings.txt", 'r') as f:
            self.a = f.readline()
            self.b = f.readline()
            self.c = f.readline()
            f.close()


            self.sm.get_screen("Screeen").ids.a.text = self.a
            self.sm.get_screen("Screeen").ids.b.text = self.b
            self.sm.get_screen("Screeen").ids.c.text = self.c


    def on_stop(self):   # after exiting the application, data from the input fields is saved to a file
        with open("settings.txt", "w") as f:
            f.write(self.sm.get_screen("Screeen").ids.a.text + "\n")
            f.write(self.sm.get_screen("Screeen").ids.b.text + "\n")
            f.write(self.sm.get_screen("Screeen").ids.c.text + "\n")


    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        # type-hint will help the IDE guide you to methods, etc.
        self.sm: ScreenManager = Builder.load_file("test.kv")


    def build(self):
        return self.sm



if __name__ == "__main__":
    appApp().run()

'''

test.kv:

'''

Manager:
    Screeen:

<Screeen>:
    name: "Screeen"
    FloatLayout:
        size: root.width, root.height
        TextInput:
            id: a
            text: ""
            size_hint: (.25, .1)
            pos: root.width * 1 / 3 , root.height * 3 / 4

        TextInput:
            id: b
            text: ""
            size_hint: (.25, .1)
            pos: root.width * 1 / 3 , root.height * 2 / 4

        TextInput:
            id: c
            text: ""
            size_hint: (.25, .1)
            pos: root.width * 1 / 3 , root.height * 1 / 4

'''

and settings.txt is empty

Answer 1

readline() will return the terminating newline. Therefore, you could rewrite the on_start() function as follows:

def on_start(self):
    _ids = self.sm.get_screen("Screeen").ids
    with open("settings.txt") as f:
        for attr in "abc":
            _ids[attr].text = f.readline().rstrip()