QLineEdit验证{[AZ] [az] [0-9]}文本输入

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QLineEdit, QLabel
from PyQt5.QtGui import QRegExpValidator
import re

class QLineEditValidator(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        self.layout = QVBoxLayout()

        self.line_edit = QLineEdit()
        self.line_edit.setPlaceholderText("输入文本")

        # 设置正则表达式验证器
        reg_exp = QRegExp("[A-Za-z0-9]*")
        validator = QRegExpValidator(reg_exp, self)
        self.line_edit.setValidator(validator)

        self.label = QLabel("输入错误")
        self.label.setStyleSheet("color: red;")
        self.label.hide()

        self.layout.addWidget(self.line_edit)
        self.layout.addWidget(self.label)

        self.setLayout(self.layout)

        self.line_edit.textChanged.connect(self.validate_input)

    def validate_input(self, text):
        if re.match("^[A-Za-z0-9]*$", text):
            self.label.hide()
        else:
            self.label.show()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = QLineEditValidator()
    window.show()
    sys.exit(app.exec_())