PyQt5 - Hello World

Creating a simple GUI apppcation using PyQt involves the following steps −

Import QtCore, QtGui and QtWidgets modules from PyQt5 package.

Create an apppcation object of QApppcation class.

A QWidget object creates top level window. Add QLabel object in it.

Set the caption of label as "hello world".

Define the size and position of window by setGeometry() method.

Enter the mainloop of apppcation by app.exec_() method.

Following is the code to execute Hello World program in PyQt −

import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
def window():
   app = QApppcation(sys.argv)
   w = QWidget()
   b = QLabel(w)
   b.setText("Hello World!")
   w.setGeometry(100,100,200,50)
   b.move(50,20)
   w.setWindowTitle("PyQt5")
   w.show()
   sys.exit(app.exec_())
if __name__ ==  __main__ :
   window()

The above code produces the following output −

It is also possible to develop an object oriented solution of the above code.

Import QtCore, QtGui and QtWidgets modules from PyQt5 package.

Create an apppcation object of QApppcation class.

Declare window class based on QWidget class

Add a QLabel object and set the caption of label as "hello world".

Define the size and position of window by setGeometry() method.

Enter the mainloop of apppcation by app.exec_() method.

Following is the complete code of the object oriented solution −

import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
class window(QWidget):
   def __init__(self, parent = None):
      super(window, self).__init__(parent)
      self.resize(200,50)
      self.setWindowTitle("PyQt5")
      self.label = QLabel(self)
      self.label.setText("Hello World")
      font = QFont()
      font.setFamily("Arial")
      font.setPointSize(16)
      self.label.setFont(font)
      self.label.move(50,20)
def main():
   app = QApppcation(sys.argv)
   ex = window()
   ex.show()
   sys.exit(app.exec_())
if __name__ ==  __main__ :
   main()