title: How to fix the width/height to specific column/row in QGridLayout?
body: <p>To this question I am referring to the example <strong>calculator.py</strong> from <a href="http://zetcode.com/gui/pyqt5/layout/" rel="nofollow noreferrer">http://zetcode.com/gui/pyqt5/layout/</a></p>
  <p>In the example the <code>QGridLayout</code> was used. I want to ask if it is possible to define the width/height to some specific columns/rows?</p>
  <p>Please see the picture.
  <a href="https://i.stack.imgur.com/aeIqA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aeIqA.png" alt="enter image description here" /></a>
  E.g. I want the second column has the width of 50px and the third row has the height 80px. So that no matter how big/small the window is, these 50px, and 80px are always shown as defined. The rest rows/columns can be scaled automatically when the window size changes.</p>
  <p>I have searched but could not find the answer.</p>
  <p>For your convenience, I paste the code here (with tiny changes to the original version)</p>
  <pre><code># -*- coding: utf-8 -*-
  
  import sys
  from PyQt5.QtWidgets import (QWidget, QGridLayout, QPushButton, QApplication)
  
  class Example(QWidget):
      def __init__(self):
          super(Example, self).__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)
  
          self.move(300, 150)
          self.setWindowTitle('Calculator')
          self.show()
  
  
  if __name__ == '__main__':
      app = QApplication(sys.argv)
      ex = Example()
      sys.exit(app.exec_())
  </code></pre>