grid_layout.py

#!/usr/bin/python3
# -*- coding: UTF-8 -*-

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

class Example(QWidget):

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

    def initUI(self):

        grid = QGridLayout()
        self.setLayout(grid)

        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)
            print(*position)
            print(grid.addWidget)

            self.setGeometry(300, 300, 500, 350)
            self.setWindowTitle('calculator')
            self.show()

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