Displaying numbers with QLCDNumber.display() with PyQt

Question

I am bit new to Qt and python. I have created a simple GUI which consist of a simple calculator. I used the QT Designer to design the GUI and now I want to link my buttons to the QLCDNumber display.

I created a *.clicked.connect(self.my_func) to link it but only the print statement is working well when clicking the button.

from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_Dialog(object):
    def setupUi(self, Dialog):
        Dialog.setObjectName("Dialog")
        self.gridLayoutWidget = QtWidgets.QWidget(Dialog)
        self.gridLayoutWidget.setGeometry(QtCore.QRect(20, 80, 164, 134))
        self.gridLayoutWidget.setObjectName("gridLayoutWidget")
        self.gridLayout = QtWidgets.QGridLayout(self.gridLayoutWidget)
        self.gridLayout.setContentsMargins(0, 0, 0, 0)
        self.gridLayout.setObjectName("gridLayout")

        self.pushButton_9 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_9.setObjectName("pushButton_9")
        self.gridLayout.addWidget(self.pushButton_9, 0, 2, 1, 1)
        self.pushButton_9.clicked.connect(self.my_func)

        self.pushButton_5 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_5.setObjectName("pushButton_5")
        self.gridLayout.addWidget(self.pushButton_5, 1, 1, 1, 1)
        self.pushButton_7 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_7.setObjectName("pushButton_7")
        self.gridLayout.addWidget(self.pushButton_7, 0, 0, 1, 1)
        self.pushButton_6 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_6.setObjectName("pushButton_6")
        self.gridLayout.addWidget(self.pushButton_6, 1, 2, 1, 1)
        self.pushButton_8 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_8.setObjectName("pushButton_8")
        self.gridLayout.addWidget(self.pushButton_8, 0, 1, 1, 1)
        self.pushButton_4 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_4.setObjectName("pushButton_4")
        self.gridLayout.addWidget(self.pushButton_4, 1, 0, 1, 1)
        self.pushButton_3 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_3.setObjectName("pushButton_3")
        self.gridLayout.addWidget(self.pushButton_3, 2, 2, 1, 1)
        self.pushButton_0 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_0.setObjectName("pushButton_0")
        self.gridLayout.addWidget(self.pushButton_0, 3, 0, 1, 3)
        self.pushButton_2 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_2.setObjectName("pushButton_2")
        self.gridLayout.addWidget(self.pushButton_2, 2, 1, 1, 1)
        self.pushButton_1 = QtWidgets.QPushButton(self.gridLayoutWidget)
        self.pushButton_1.setObjectName("pushButton_1")
        self.gridLayout.addWidget(self.pushButton_1, 2, 0, 1, 1)
        self.pushButton_6.raise_()
        self.pushButton_5.raise_()
        self.pushButton_4.raise_()
        self.pushButton_1.raise_()
        self.pushButton_2.raise_()
        self.pushButton_3.raise_()
        self.pushButton_8.raise_()
        self.pushButton_9.raise_()
        self.pushButton_0.raise_()
        self.pushButton_7.raise_()

        self.lcdNumber = QtWidgets.QLCDNumber(Dialog)
        self.lcdNumber.setGeometry(QtCore.QRect(20, 10, 221, 61))
        self.lcdNumber.setObjectName("lcdNumber")

        self.gridLayoutWidget_2 = QtWidgets.QWidget(Dialog)
        self.gridLayoutWidget_2.setGeometry(QtCore.QRect(190, 80, 51, 134))
        self.gridLayoutWidget_2.setObjectName("gridLayoutWidget_2")
        self.gridLayout_2 = QtWidgets.QGridLayout(self.gridLayoutWidget_2)
        self.gridLayout_2.setContentsMargins(0, 0, 0, 0)
        self.gridLayout_2.setObjectName("gridLayout_2")
        self.pushButton_10 = QtWidgets.QPushButton(self.gridLayoutWidget_2)
        self.pushButton_10.setObjectName("pushButton_10")
        self.gridLayout_2.addWidget(self.pushButton_10, 2, 0, 1, 1)
        self.pushButton = QtWidgets.QPushButton(self.gridLayoutWidget_2)
        self.pushButton.setObjectName("pushButton")
        self.gridLayout_2.addWidget(self.pushButton, 1, 0, 1, 1)
        self.pushButton_11 = QtWidgets.QPushButton(self.gridLayoutWidget_2)
        self.pushButton_11.setObjectName("pushButton_11")
        self.gridLayout_2.addWidget(self.pushButton_11, 3, 0, 1, 1)
        self.pushButton_12 = QtWidgets.QPushButton(self.gridLayoutWidget_2)
        self.pushButton_12.setObjectName("pushButton_12")
        self.gridLayout_2.addWidget(self.pushButton_12, 0, 0, 1, 1)
        self.label = QtWidgets.QLabel(Dialog)
        self.label.setGeometry(QtCore.QRect(20, 230, 60, 16))
        self.label.setObjectName("label")

        self.retranslateUi(Dialog)
        QtCore.QMetaObject.connectSlotsByName(Dialog)


    def my_func(self):
        print("Works")
        self.lcdNumber.display(9)


    def retranslateUi(self, Dialog):
        _translate = QtCore.QCoreApplication.translate
        Dialog.setWindowTitle(_translate("Dialog", "Dialog"))
        self.pushButton_9.setText(_translate("Dialog", "9"))
        self.pushButton_5.setText(_translate("Dialog", "5"))
        self.pushButton_7.setText(_translate("Dialog", "7"))
        self.pushButton_6.setText(_translate("Dialog", "6"))
        self.pushButton_8.setText(_translate("Dialog", "8"))
        self.pushButton_4.setText(_translate("Dialog", "4"))
        self.pushButton_3.setText(_translate("Dialog", "3"))
        self.pushButton_0.setText(_translate("Dialog", "0"))
        self.pushButton_2.setText(_translate("Dialog", "2"))
        self.pushButton_1.setText(_translate("Dialog", "1"))
        self.pushButton_10.setText(_translate("Dialog", "-"))
        self.pushButton.setText(_translate("Dialog", "+"))
        self.pushButton_11.setText(_translate("Dialog", "="))
        self.pushButton_12.setText(_translate("Dialog", "DEL"))
        self.label.setText(_translate("Dialog", "TextLabel"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Dialog = QtWidgets.QDialog()
    ui = Ui_Dialog()
    ui.setupUi(Dialog)
    Dialog.show()
    sys.exit(app.exec_())

Answer 1

Try it:

import sys
from PyQt5.QtWidgets import (QWidget, QPushButton, QApplication, 
                             QGridLayout, QLCDNumber)

class Example(QWidget):
    def __init__(self):
        super().__init__()
        self.Init_UI()

    def Init_UI(self):
        self.setGeometry(750, 300, 400, 300)
        self.setWindowTitle('QGridLayout-QLCDNumber-calculator')

        grid = QGridLayout()
        self.setLayout(grid)        

        self.lcd = QLCDNumber()
        grid.addWidget(self.lcd, 0, 0, 3, 0)
        grid.setSpacing(10)

        names = ['Cls', 'Bc', '',  'Close',
                 '7',   '8',  '9', '/',
                 '4',   '5',  '6', '*',
                 '1',   '2',  '3', '-',
                 '0',   '.',  '=', '+']

        positions = [(i,j) for i in range(4,9) for j in range(4,8)]

        for position, name in zip(positions, names):
            print("position=`{}`, name=`{}`".format(position, name))
            if name == '':
                continue

            button = QPushButton(name)

            grid.addWidget(button, *position)

            button.clicked.connect(self.Cli)

        self.show()

    def Cli(self):
        sender = self.sender().text()
        ls = ['/', '*', '-', '=', '+']
        if sender in ls:
            self.lcd.display('A')
        else:
            self.lcd.display(sender)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    app.exit(app.exec_())