pyQt5_layout.py

import sys
from PyQt5.QtWidgets import QWidget, QApplication,\
QPushButton, QHBoxLayout, QVBoxLayout

class Example(QWidget):

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

        self.initUI()


    def initUI(self):

        okButton = QPushButton("OK")
        cancelButton = QPushButton("Cancel")

        hbox = QHBoxLayout()
        hbox.addStretch(1)
        hbox.addWidget(okButton)
        hbox.addWidget(cancelButton)

        vbox = QVBoxLayout()
        vbox.addStretch(1)
        vbox.addLayout(hbox)

        self.setLayout(vbox)
        self.setLayout(hbox)

        self.setGeometry(300, 300, 300, 150)
        self.setWindowTitle('Buttons')
        self.show()


if __name__ == '__main__':

    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())