看不到一个函数的输出等于一个字符串

Question

我有一个程序，只要我按下一个按钮，它就会将一个值写入一个文本文件。下次按下按钮时，它会找到最后写入的字符串并调用变量来执行相反的操作。这一直是运行，直到我将其关闭。我的问题是它不会停止打印“Off”，这是我的文本文件中的最后一个字符串。当程序运行时，Fine() 打印文本文件的最后一个字符串，然后进入 while 循环。它似乎无法识别我的 if 语句，只是再次打印 Fine() 而不做任何更改。我不知道为什么它一直打印“关闭”这可能是我不知道的格式化问题，但我已经看过但找不到类似的东西。

import time
import os
# this is the system that detects the last line. In order to seek the end of file, we have to open the file in binary mode. We seek the last 2 characters
# since the file is likely to end with a newline. Then, keep reading a single byte until a newline character is found. And, finally, we use readline() to read the \
# final line, and decode() to convert from bytes to string.


# Checker is a fall back system so if there is nothing in the file then it writes on(or the terms i am using at that time.) so that when I press the button again it starts the cycle.

def Checker():
    file = open("Store.txt").readlines()
    #print(file[0:2])
    if file[0:2] != ['On\n', 'Off']:
        print("nothing is here...Restarting file with added Off")
        with open("Store.txt","w") as df:
            df.write("On\nOff")
            df.close()
    
def Fine():
    with open("Store.txt", "rb") as f:
        f.seek(-2, os.SEEK_END)
        while f.read(1) != b'\n':
            f.seek(-2, os.SEEK_CUR) 
        print(f.readline().decode())


def w_on():
    print("The light is on")
    with open("Store.txt", "w") as on:
        on.write("On\n","On")
        on.close()


def w_off():
    print("this is off")
    with open ("Store.txt", "w") as off:
        off.write("off\no","OFFF")
        off.close()
    


#This checks the status of the text file and corrects it if the text inside is wrong.
Checker()
# this prints the current last line in the Store.txt file.
Fine()


#============================================================================================
#Here is the start of my Issue of it printing "Off"

# 1==1 replaces the button.pressed() function    
while True:
    time.sleep(1)
    if 1==1:
        if Fine()==("On"):
            # the print function replaces the function for the servo moving. right here the off funtion would happen.
            print("The light is turning off")
            w_off()

        elif Fine()== ("Off"):
            # the print fucntion replaces the function for the serveo moving. right below, the on funtion would happen.
            print("The light is turning on")
            w_on()


    time.sleep(2)

Answer 1

就是这一行：print(f.readline().decode())

所以在你第一次执行时，你用 On 和 Off 编写了文件，并用 Off 作为文件中的最后一条语句。

现在每次在 while 循环中调用 Fine() 时，上面的语句都会打印最后一行，即当前的 Off。

你的 Fine() 调用是 returning None（因为你的函数没有 return 任何东西），因此你的 if 和 elif 除了调用 Fine() 来检查它的值外，并没有真正执行。所以没有任何内容写入您的文件，您不断得到最后一行仍然是 Off.

Answer 2

我更改了 if 语句正在读取的变量，我能够解决这个问题。

# 1==1 replaces the button.pressed() function    
while True:
    time.sleep(1)
    
    with open("Store.txt", "rb") as f:
        f.seek(-2, os.SEEK_END)
        while f.read(1) != b'\n':
            f.seek(-2, os.SEEK_CUR)
        # Adeed the var Detect so I can tell the output of the reading.
        Detect = f.readline().decode()
        f.close()
        
        # Now it asks what the output of the reading is not the output of a function, so it continues through instead of returning a None.
        if Detect==("On"):
            # the print function replaces the function for the servo moving. right here the off function would happen.
            print("The light is turning off")
            w_off()

        elif Detect== ("Off"):
            # the print fucntion replaces the function for the serveo moving. right below, the on funtion would happen.
            print("The light is turning on")
            w_on()
        else:
            print("Incorrect")


    time.sleep(2)

看不到一个函数的输出等于一个字符串

Can't see the output of a function is equal to a string

python

text-files

python-3.x