This is a school project (notebook), I am starting and i am a newbie, the code below
is what i am still struggling with…since i am building a GUI.

import sys
from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtGui import QIcon
class App(QWidget):
    def __init__(self):
        super().__init__()
        self.title='Hello, world!'
        self.left=10
        self.top=10
        self.width=-640
        self.height+=400

    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left,self.top,self.width,self.height)
        show()

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

>Solution :

Try my fix

I added self.initUI() to launch your function that give title name and show Your QWidget app

I replaced your last line with sys.exit(app.exec_())

— Full fix code —

import sys
from PyQt5.QtWidgets import QApplication, QWidget
from PyQt5.QtGui import QIcon
class App(QWidget):
    def __init__(self):
        super().__init__()
        self.title='Hello, world!'
        self.left=10
        self.top=10
        self.width=640
        self.height=480
        self.initUI()
    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left,self.top,self.width,self.height)
        self.show()
if __name__=='__main__':
    app=QApplication(sys.argv)
    ex=App()
    sys.exit(app.exec_())