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

class Example(QWidget):

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

    def setUI(self):
        h1box = QHBoxLayout()

        line_edit = QLineEdit()
        button = QPushButton("Submit")
        button.clicked.connect(self.buttonClicked)

        h1box.addWidget(line_edit)
        h1box.addWidget(button)

        h2box = QHBoxLayout()
        label = QLabel("0")
        h2box.addWidget(label)

        vbox = QVBoxLayout()

        vbox.addLayout(h1box)
        vbox.addLayout(h2box)
        self.setLayout(vbox)
        self.show()

    def buttonClicked(self):
        # label needs to be filled with LineEdit value

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

sys.exit(app.exec_())