33 restrict the input of qlineedit control (verifier)

Limit input to integers only 、 Floating point number or string satisfying certain conditions

from PyQt5.QtWidgets import *
from PyQt5.QtGui import QIntValidator, QDoubleValidator, QRegExpValidator
from PyQt5.QtCore import QRegExp
import sys

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

    def initUI(self):
        self.setWindowTitle(' Calculator ')
        #  Create form layout 
        formLayout = QFormLayout()

        intLineEdit = QLineEdit()
        doubleLineEdit = QLineEdit()
        regLineEdit = QLineEdit()

        intLineEdit.setPlaceholderText(' Integers ')
        doubleLineEdit.setPlaceholderText(' floating-point ')
        regLineEdit.setPlaceholderText(' Letters and numbers ')

        #  Integer verifier [1, 99]
        intValidator = QIntValidator(self)
        intValidator.setRange(1, 99)

        #  Floating point verifier [-360, 360], precision ： Two decimal places 
        doubleValidator = QDoubleValidator(self)
        doubleValidator.setRange(-360, 360)
        doubleValidator.setNotation(QDoubleValidator.StandardNotation)
        #  Setting accuracy , Two decimal places 
        doubleValidator.setDecimals(2)

        #  Characters and numbers 
        reg = QRegExp('[a-zA-Z0-9]+$')
        validator = QRegExpValidator(self)
        validator.setRegExp(reg)

        #  Set the calibrator 
        intLineEdit.setValidator(intValidator)
        doubleLineEdit.setValidator(doubleValidator)
        regLineEdit.setValidator(validator)

        formLayout.addRow(' Integer types ', intLineEdit)
        formLayout.addRow(' Floating point type ', doubleLineEdit)
        formLayout.addRow(' Alphanumeric ', regLineEdit)


        self.setLayout(formLayout)

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