readline（）代码在我的python应用程序中无法正常工作。为什么？

Question

我正在通过python3.8.3和pyqt5构建一个应用程序。这是我的代码的一部分：

def logupd(self):
        users=open('NeveshtarUsers.txt', 'w')
        users.write('Username: ')
        users.write(self.user2.text())
        users.write(' Password: ')
        users.write(self.pass2.text())
        users.write('.\n')
        users.write('Name: ')
        users.write(self.name.text())
        users.write('.\n')
        users.write('....................\n')
        self.no.setText('Loggind up has succesed. Please Login')

        with open('NeveshtarUsers.txt') as file:
            print('salam')
            data = file.readlines()
            print(data)

当我调用此代码时，输​​出为：

salam
[]

为什么数据为空？有什么问题吗？

Answer 1

我认为问题不是关闭在写模式下打开的文件

def logupd(self):
        users=open('NeveshtarUsers.txt', 'w')
        users.write('Username: ')
        users.write(self.user2.text())
        users.write(' Password: ')
        users.write(self.pass2.text())
        users.write('.\n')
        users.write('Name: ')
        users.write(self.name.text())
        users.write('.\n')
        users.write('....................\n')
        self.no.setText('Loggind up has succesed. Please Login')
        # close the file that is opened in write , the text will get updated to the system's memory 
        # only when the file is closed 
        users.close()
        with open('NeveshtarUsers.txt') as file:
            print('salam')
            data = file.readlines()
            print(data)