12. PyQt6 QGridLayout

import sys
from PyQt6.QtWidgets import QApplication, QMainWindow, QGridLayout, QPushButton, QWidget
from PyQt6.QtGui import QGuiApplication


class App(QMainWindow):

    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle("PyQt6 QGridLayout")
        grid = QGridLayout()

        w = QWidget()
        w.setLayout(grid)
        self.setCentralWidget(w)

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

        positions = [(i, j) for i in range(5) for j in range(4)]

        for position, name in zip(positions, names):

            if name == '':
                continue

            button = QPushButton(name)
            grid.addWidget(button, *position)

        self.setGeometry(100, 100, 400, 300)
        self.center()

    def center(self):
        qr = self.frameGeometry()
        cp = QGuiApplication.primaryScreen().availableGeometry().center()
        qr.moveCenter(cp)
        self.move(qr.topLeft())


if __name__ == "__main__":
    app = QApplication(sys.argv)
    cls_app = App()
    cls_app.show()
    sys.exit(app.exec())