Is there a way to clear all but 1 specific row in QListWİdget

Question

There are two types of rows one is Pizza and the other one is Client.

def addClient(self):
    self.listWidget.clear()
    self.listWidget.addItem("client")

When new row 'Client' added i can clear all other rows but when i add another Client my first client row is getting deleted too i want the first client to not be affected by clear function.Example of rows;

-Client(first)
-Pizza
-Pizza

When i add new Client;

-Client(first)
-Client(second)

When i add couple of pizza rows;

-Client(first)
-Client(second)
-Pizza
-Pizza

Finally when i add another Client;

-Client(first)
-Client(second)
-Client(third)

As i CLEARLY show it i want to keep every Client rows when i use clear function and clear any other rows.

Answer 1

You do not have to use clear(), what you have to do is filter the items that have "Pizza" as text and delete them one by one from the QListWidget:

from PyQt5 import QtCore, QtWidgets

class Widget(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        self.list_widget = QtWidgets.QListWidget()
        client_btn = QtWidgets.QPushButton("add client")
        client_btn.clicked.connect(self.add_client)
        pizza_btn = QtWidgets.QPushButton("add pizza")
        pizza_btn.clicked.connect(self.add_pizza)

        grid = QtWidgets.QGridLayout(self)
        grid.addWidget(self.list_widget, 0, 0, 1, 2)
        grid.addWidget(client_btn, 1, 0)
        grid.addWidget(pizza_btn, 1, 1)

    @QtCore.pyqtSlot()
    def add_client(self):
        client_items = self.list_widget.findItems(
            "Pizza",
            QtCore.Qt.MatchExactly
        ) 
        for item in reversed(client_items):
            row = self.list_widget.row(item)
            it = self.list_widget.takeItem(row)
            del it
        self.list_widget.addItem("Client")

    @QtCore.pyqtSlot()
    def add_pizza(self):
        self.list_widget.addItem("Pizza")

if __name__ == '__main__':
    import sys
    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())