Python. The Validator does not allow you to erase the value of the TableWidget. Has anyone experienced this?

Question

Python

Hello! If anyone has come across or knows how to solve it, please tell me ... I
drew a tableWidget, hung validators (double, int).
When I enter a value into a cell, the validator works, everything is ok. But when I want to clear a previously entered cell, the value is not erased.
Can you please tell me how to get around this problem?
My example:

# -*- coding: utf-8 -*-

from PyQt5 import QtCore, QtGui, QtWidgets
import datetime
from PyQt5.QtWidgets import QMainWindow, QAction, qApp, QApplication, QDialog, QVBoxLayout
from PyQt5.Qt import QLabel, QDialogButtonBox, Qt

class ValidatedItemDelegate(QtWidgets.QStyledItemDelegate):
    def __init__(self, parent = None):
        super(ValidatedItemDelegate, self).__init__(parent) 
    def createEditor(self, parent, option, index):
        if not index.isValid():
            return 0
        if index.column() == 0 or index.column() == 2:
            editor = QtWidgets.QLineEdit(parent)
            validator = QtGui.QDoubleValidator()
            editor.setValidator(validator)
            return editor
        if index.column() == 1:
            editor = QtWidgets.QLineEdit(parent)
            #validator = QtGui.QDoubleValidator()
            validator = QtGui.QIntValidator()
            editor.setValidator(validator)
            return editor
        return super(ValidatedItemDelegate, self).createEditor(parent, option, index)
  
class Ui_Primer(QtWidgets.QWidget):
    def setupUi(self, Primer):
        Primer.setObjectName("Primer")
        Primer.setFixedSize(290, 245)
        self.groupBox = QtWidgets.QGroupBox(Primer)
        self.groupBox.setGeometry(QtCore.QRect(15, 15, 260, 215))
        self.groupBox.setTitle("")
        self.groupBox.setObjectName("groupBox")
        self.tableWidget = QtWidgets.QTableWidget(self.groupBox)
        self.tableWidget.setGeometry(QtCore.QRect(20, 20, 222, 175))
        self.tableWidget.setObjectName("tableWidget")
        self.tableWidget.setColumnCount(2)
        self.tableWidget.setRowCount(6)   
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(0, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(1, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(2, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(3, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(4, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setVerticalHeaderItem(5, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(0, item)
        item = QtWidgets.QTableWidgetItem()
        self.tableWidget.setHorizontalHeaderItem(1, item)
        i = 0
        while i <= 6:
            item = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(i, 0, item)
            i = i + 1
        i = 0
        while i <= 6:
            item = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(i, 1, item)
            i = i + 1
        i = 0
        while i <= 6:
            item = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(i, 2, item)
            i = i + 1
        i = 0
        while i <= 6:
            item = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(i, 3, item)
            i = i + 1
        i = 0
        while i <= 6:
            item = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(i, 4, item)
            i = i + 1
        i = 0
        while i <= 6:
            item = QtWidgets.QTableWidgetItem()
            self.tableWidget.setItem(i, 5, item)
            i = i + 1        
        #start - Вешаем валидатор
        self.tableWidget.setItemDelegate(ValidatedItemDelegate())
        #end - Вешаем валидатор 
        self.tableWidget.horizontalHeader().setVisible(True)
        self.tableWidget.horizontalHeader().setDefaultSectionSize(110)
        self.tableWidget.horizontalHeader().setHighlightSections(False)
        self.tableWidget.horizontalHeader().setMinimumSectionSize(25)
        self.tableWidget.verticalHeader().setVisible(False)
        self.tableWidget.verticalHeader().setDefaultSectionSize(25)
        self.tableWidget.verticalHeader().setMinimumSectionSize(25)
        self.retranslateUi(Primer)
        QtCore.QMetaObject.connectSlotsByName(Primer)
        
    def retranslateUi(self, Primer):
        _translate = QtCore.QCoreApplication.translate
        Primer.setWindowTitle(_translate("Primer", "Пример"))
        item = self.tableWidget.verticalHeaderItem(0)
        item.setText(_translate("Primer", "1"))
        item = self.tableWidget.verticalHeaderItem(1)
        item.setText(_translate("Primer", "2"))
        item = self.tableWidget.verticalHeaderItem(2)
        item.setText(_translate("Primer", "3"))
        item = self.tableWidget.verticalHeaderItem(3)
        item.setText(_translate("Primer", "4"))
        item = self.tableWidget.verticalHeaderItem(4)
        item.setText(_translate("Primer", "6"))
        item = self.tableWidget.horizontalHeaderItem(0)
        item.setText(_translate("Primer", "-- Double --"))
        item = self.tableWidget.horizontalHeaderItem(1)
        item.setText(_translate("Primer", "-- Int --"))
        item = self.tableWidget.horizontalHeaderItem(2)
    
if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    Primer = QtWidgets.QWidget()
    ui = Ui_Primer()
    ui.setupUi(Primer)
    Primer.show()
    sys.exit(app.exec_())

Answer 1

In general, in Qt, if you don’t like something, you need to inherit and rewrite the method, changing the behavior to the desired one - this is the standard way in Qt, unfortunately.
Like this:

class MyDoubleValidator(QtGui.QDoubleValidator):
    def __init__(self, *args):
        super(MyDoubleValidator, self).__init__(*args)

    def validate(self, string, number):
        if not string:
            return (QtGui.QValidator.Acceptable, string, number)
        return QtGui.QDoubleValidator().validate(string, number)

after:
validator = MyDoubleValidator()