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Forum Update on Monday, May 27th 2025

insertRows and insertRow in tableview

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  • B blossomsg

    Hey all,
    This is a continuation of my previous post
    https://forum.qt.io/topic/130364/headerdata-of-qabstracttablemodel-unable-to-return-qtcore-qvariant-list-of-strings/6

    expecting_a_5th_row.jpg

    I am trying to insertRows through insertRow -- expecting 5th row
    as per the docs
    but i guess i am doing something wrong, i know i am suppose to put rowCount somewhere in insertRows or insertRow

    and if you can elaborate difference between rowCount and insertRows or insertRow

    can you please guide me through

    from PyQt5 import QtCore
    
    
    class TableModel(QtCore.QAbstractTableModel):
    	def __init__(self, cols_strings, rows_strings, empty_strings, parent=None):
    		super(TableModel, self).__init__(parent)
    
    		self.colStringsList = cols_strings
    		self.rowStringsList = rows_strings
    		self.data = empty_strings
    
    	def rowCount(self, index=QtCore.QModelIndex()):
    		return len(self.data)
    
    	def columnCount(self, index=QtCore.QModelIndex()):
    		return len(self.data[0])
    
    	def data(self, index=QtCore.QModelIndex, role=QtCore.Qt.DisplayRole):
    		if index.isValid():
    			if role == QtCore.Qt.DisplayRole or role == QtCore.Qt.EditRole:
    				value = self.data[index.row()][index.column()]
    				return str(value)
    
    	def setData(self, index=QtCore.QModelIndex, value=QtCore.QVariant, role=QtCore.Qt.EditRole):
    		if role == QtCore.Qt.EditRole:
    			self.data[index.row()][index.column()] = value
    			return True
    		return False
    
    	def headerData(self, section, orientation=QtCore.Qt.Orientation, role=QtCore.Qt.DisplayRole):
    		if role == QtCore.Qt.DisplayRole:
    			if orientation == QtCore.Qt.Horizontal:
    				return self.colStringsList[section]
    			if orientation == QtCore.Qt.Vertical:
    				return self.rowStringsList[section]
    
    	def flags(self, index):
    		return QtCore.Qt.ItemIsSelectable | QtCore.Qt.ItemIsEnabled | QtCore.Qt.ItemIsEditable
    
    	def insertRow(self, position, index=QtCore.QModelIndex()):
    		self.insertRows(position, 1, index)
    
    	def insertRows(self, position, rows=1, index=QtCore.QModelIndex()):
    		self.beginInsertRows(index, position, position + rows - 1)
    		for row in range(0, rows):
    			self.data.insert(position, "")
    		self.endInsertRows()
    		return True
    
    
    jeremy_kJ Offline
    jeremy_kJ Offline
    jeremy_k
    wrote on last edited by
    #5

    @blossomsg said in insertRows and insertRow in tableview:

    	def data(self, index=QtCore.QModelIndex, role=QtCore.Qt.DisplayRole):
    		if index.isValid():
    			if role == QtCore.Qt.DisplayRole or role == QtCore.Qt.EditRole:
    				value = self.data[index.row()][index.column()]
    				return str(value)
    
    	def insertRows(self, position, rows=1, index=QtCore.QModelIndex()):
    		self.beginInsertRows(index, position, position + rows - 1)
    		for row in range(0, rows):
    			self.data.insert(position, "")
    		self.endInsertRows()
    		return True
    
    

    TableModel.insertRows() is inserting an empty string into data. TableModel.data() attempts to index into that string, which will fail.

    Asking a question about code? http://eel.is/iso-c++/testcase/

    1 Reply Last reply
    1
    • B Offline
      B Offline
      blossomsg
      wrote on last edited by
      #6

      Hey @jeremy_k
      thanks for reply.
      in the ui class i am passing list of empty strings, as i don't want it prefilled
      i assumed model will be enough to explain the situation
      below is the ui code
      i am looking for how to get n-number of rows with insertRows, but no success

      from ui.table_view_delgate import Ui_Form
      from tablemodel import TableModel
      from PyQt5 import QtWidgets
      from PyQt5 import QtGui
      import sys
      import json
      
      with open('configuration_file.json') as data:
      	config = json.load(data)
      table_strings = config
      
      
      class TableView(QtWidgets.QWidget):
      	"""
      	Tableview to test the delegates for multiple rows and columns
      	"""
      
      	def __init__(self):
      		super(TableView, self).__init__()
      		self.ui = Ui_Form()
      		self.ui.setupUi(self)
                      # this is coming from json, you can change to normal list as well
      		self.table_col_names = [col for col in config.keys()]
      		self.table_row_names = [row for row in range(10)]
      		self.empty = [["", ""], ["", ""], ["", ""], ["", ""], ["", ""]]
      		self.model = TableModel(self.table_col_names, self.table_row_names, self.empty)
      		self.ui.tableView.setModel(self.model)
      
      
      app = QtWidgets.QApplication(sys.argv)
      app.setStyle('windows')
      window = TableView()
      window.show()
      sys.exit(app.exec_())
      
      JonBJ 1 Reply Last reply
      0
      • B blossomsg

        Hey @jeremy_k
        thanks for reply.
        in the ui class i am passing list of empty strings, as i don't want it prefilled
        i assumed model will be enough to explain the situation
        below is the ui code
        i am looking for how to get n-number of rows with insertRows, but no success

        from ui.table_view_delgate import Ui_Form
        from tablemodel import TableModel
        from PyQt5 import QtWidgets
        from PyQt5 import QtGui
        import sys
        import json
        
        with open('configuration_file.json') as data:
        	config = json.load(data)
        table_strings = config
        
        
        class TableView(QtWidgets.QWidget):
        	"""
        	Tableview to test the delegates for multiple rows and columns
        	"""
        
        	def __init__(self):
        		super(TableView, self).__init__()
        		self.ui = Ui_Form()
        		self.ui.setupUi(self)
                        # this is coming from json, you can change to normal list as well
        		self.table_col_names = [col for col in config.keys()]
        		self.table_row_names = [row for row in range(10)]
        		self.empty = [["", ""], ["", ""], ["", ""], ["", ""], ["", ""]]
        		self.model = TableModel(self.table_col_names, self.table_row_names, self.empty)
        		self.ui.tableView.setModel(self.model)
        
        
        app = QtWidgets.QApplication(sys.argv)
        app.setStyle('windows')
        window = TableView()
        window.show()
        sys.exit(app.exec_())
        
        JonBJ Online
        JonBJ Online
        JonB
        wrote on last edited by
        #7

        @blossomsg
        But when you insert a new row you go:

        self.data.insert(position, "")
        

        That is a single string, not an array/list of strings corresponding to each column, which is what you have in your self.empty?

        1 Reply Last reply
        0
        • B Offline
          B Offline
          blossomsg
          wrote on last edited by
          #8

          Hey @JonB ,
          thanks for replying
          i guess what you're saying is, this what i am suppose to do?
          i tried with regular list, nested list, but no success
          self.data.insert(position, ["", ""])
          and
          i even tried vice versa, updated
          self.empty with ["", ""] and "" -- no success

          JonBJ 1 Reply Last reply
          0
          • B blossomsg

            Hey @JonB ,
            thanks for replying
            i guess what you're saying is, this what i am suppose to do?
            i tried with regular list, nested list, but no success
            self.data.insert(position, ["", ""])
            and
            i even tried vice versa, updated
            self.empty with ["", ""] and "" -- no success

            JonBJ Online
            JonBJ Online
            JonB
            wrote on last edited by
            #9

            @blossomsg said in insertRows and insertRow in tableview:

            self.data.insert(position, ["", ""])

            From what I can in self.empty one row is indeed ["", ""], so that insert() looks better than "".

            but when i run the above code(model) with ui the 5th row does not appear

            What is the question/situation/problem? The code you show doesn't actually call any insertRow() or insertRows()? What 5th row?

            1 Reply Last reply
            0
            • B Offline
              B Offline
              blossomsg
              wrote on last edited by
              #10

              @JonB said in insertRows and insertRow in tableview:

              one row is indeed

              What i am looking for,
              right now there are 0 to 4 rows
              and 2 columns
              i want additional rows after 4th row through insertRows() is that possible?and if so how?
              i don't want to mess with or keep adding again and again empty "" in the self.empty

              JonBJ 1 Reply Last reply
              0
              • B blossomsg

                @JonB said in insertRows and insertRow in tableview:

                one row is indeed

                What i am looking for,
                right now there are 0 to 4 rows
                and 2 columns
                i want additional rows after 4th row through insertRows() is that possible?and if so how?
                i don't want to mess with or keep adding again and again empty "" in the self.empty

                JonBJ Online
                JonBJ Online
                JonB
                wrote on last edited by JonB
                #11

                @blossomsg said in insertRows and insertRow in tableview:

                i want additional rows after 4th row through insertRows() is that possible?and if so how?

                Of course. Just call self.model.insertRow(5). You seem to have written your method for inserting rows but not called it.

                i don't want to mess with or keep adding again and again empty "" in the self.empty

                I don't know what this means. The row you add will be empty because that's how you create it. Whether a row is inserted or not you can update its column values via setData().

                1 Reply Last reply
                1
                • B Offline
                  B Offline
                  blossomsg
                  wrote on last edited by blossomsg
                  #12

                  @JonB Thanks mate, you solved the mystery
                  so i am using the below code -- i am creating rows=3 rows of ["", ""] -- as you had corrected me for ""
                  rest everything is same
                  and the biggest part that i missed was self.model.insertRow(5)

                  Of course. Just call self.model.insertRow(5). You seem to have written your method for inserting rows but not called it.
                  

                  I assumed insertRow to work as data and setData , i had no clue we need to call it
                  i had even downloaded the PyQt5 repo -- examples\itemviews\editabletreemodel\editabletreemodel.py
                  it was really confusing

                  	def insertRow(self, position, index=QtCore.QModelIndex()):
                  		self.insertRows(position, 3, index)
                  
                  	def insertRows(self, position, rows, parent=QtCore.QModelIndex()):
                  		print(position, rows, parent)
                  		self.beginInsertRows(parent, position, position + rows - 1)
                  		for rows in range(0, rows):
                  			self.data.insert(position, ["", ""])
                  		self.endInsertRows()
                  		return True
                  
                  1 Reply Last reply
                  0
                  • B Offline
                    B Offline
                    blossomsg
                    wrote on last edited by
                    #13

                    Thank You all
                    But i would like to even add one more thing, as per the docs
                    https://doc.qt.io/qt-5/qabstractitemmodel.html#rowCount
                    When implementing a table based model, rowCount() should return 0 when the parent is valid.

                    and i am doing quite the opposite, i am creating my rows from rowCount()

                    https://doc.qt.io/qt-5/qabstractitemmodel.html#insertRow
                    https://doc.qt.io/qt-5/qabstractitemmodel.html#insertRows

                    so just for clarity which is the most preferred method, if there is any example page besides the mvc, please do share.

                    1 Reply Last reply
                    0
                    • C Offline
                      C Offline
                      ChrisW67
                      wrote on last edited by
                      #14

                      QAbstractItemModel::rowCount() has nothing to do with creating new rows in the model: it returns the current size and, as a const method, cannot modify the model. The documentation note, "When implementing a table based model, rowCount() should return 0 when the parent is valid," means exactly what it says. Top level items in a model have an invalid parent model index. There is no hierarchy in a table model, so there are no children of other items; all items are top level items. If anything calls your rowCount() on a table model and specifies anything other than an invalid index as the parent (it shouldn't, something is buggy) then the function should return 0 as a defensive response.

                      To create a new row or rows in your table model you call insertRow() or insertRows() and specify at which row you wish to insert the new row. The value rowCount() returns changes after this call.

                      1 Reply Last reply
                      1
                      • B Offline
                        B Offline
                        blossomsg
                        wrote on last edited by
                        #15

                        Hey guys,
                        Thanks a bunch, in all i wanted to understand the insertRows and insertRow, plus how to implement it.
                        You guys directed me in right direction
                        Thank You.
                        marking resolved

                        1 Reply Last reply
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