python PyQt如何安装及使用？

pip install PyQt5

import sys

from PyQt5.QtWidgets import *

app = QApplication(sys.argv)

win = QWidget()

win.resize(400, 100)

win.setWindowTitle('PyQt5')

label = QLabel("这是一个PyQt5应用程序！", win)

win.show()

sys.exit(app.exec_())