将数据传递给函数的问题

要将某些内容传递给函数/方法，您可以使用lambda.

它看起来像这样：

self.pushButton.clicked.connect(lambda ch, x='0':  self.null(x))

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.Qt import *

class Window(QWidget):
    def __init__(self):
        super().__init__()

        self.math = ""
        self.realmath = ""

        self.pushButton = QPushButton('0')
        self.pushButton.clicked.connect(lambda ch, x='0':  self.null(x))

        self.pushButton_7 = QPushButton('1')
        self.pushButton_7.clicked.connect(lambda ch, x='1':  self.slot(x))

        layout = QVBoxLayout(self)
        layout.addWidget(self.pushButton)
        layout.addWidget(self.pushButton_7)
        # ...

        '''
        ui.pushButton.clicked.connect(null(0))
        ui.pushButton_7.clicked.connect(slot) #1
        ui.pushButton_8.clicked.connect(slot) #2
        ui.pushButton_5.clicked.connect(slot) #3
        ui.pushButton_11.clicked.connect(slot) #4
        ui.pushButton_12.clicked.connect(slot) #5
        ui.pushButton_9.clicked.connect(slot) #6
        ui.pushButton_15.clicked.connect(slot) #7
        ui.pushButton_16.clicked.connect(slot) #8
        ui.pushButton_13.clicked.connect(slot) #9

        ui.pushButton_2.clicked.connect(slot) # .
        ui.pushButton_4.clicked.connect(slot) # +
        ui.pushButton_6.clicked.connect(slot) # -
        ui.pushButton_10.clicked.connect(slot) # x
        ui.pushButton_14.clicked.connect(slot) # /
        ui.pushButton_18.clicked.connect(slot) # (
        ui.pushButton_19.clicked.connect(slot) # ^
        ui.pushButton_20.clicked.connect(slot) # )

        ui.pushButton_17.clicked.connect('C')             # не правильно

        ui.pushButton_3.clicked.connect('=')              # не правильно
        '''

    def slot(self, x):
#        pass
        self.realmath += str(x)
        self.math += str(x)
        print(f'slot: realmath={self.realmath}, math={self.math}')



    def null(self, x):
#        global math, realmath                  # глобальные переменные это ЗЛО !
        self.realmath += str(x)
        self.math += str(x)
#        print(self.realmath)
        print(f'null: realmath={self.realmath}, math={self.math}')


if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = Window()
    w.show()
    sys.exit(app.exec_())