PyQt5：为pandas表模型实现removeRows

Question

我使用 QTableView 来显示和编辑 Pandas DataFrame。 我在 TableModel 类中使用此方法来删除行：

  def removeRows(self, position, rows, QModelIndex):
        start, end = position, rows 
        self.beginRemoveRows(QModelIndex, start, end) #
        self._data.drop(position,inplace=True)
        self._data.reset_index(drop=True,inplace=True)
        self.endRemoveRows() #
        self.layoutChanged.emit()
        return True

它工作正常，直到我将组合框添加到 TableView 上的某些单元格。我使用以下代码添加组合框（在 Main 类中），但是当我删除一行时，它会显示错误消息（Python 3.10，Pandas 1.4.1）： IndexError：索引 2 超出尺寸为 2 的轴 0 的范围 或（Python 3.9、Pandas 1.3.5）：'IndexError：单个位置索引器超出范围'

        count=len(combo_type)
        for type in combo_type:
            for row_num in range(self.model._data.shape[0]):
                # print(i)
                combo = CheckableComboBox(dept_list,self.model._data,row_num,type,count)
                self.tableView.setIndexWidget(self.model.index(row_num, self.model._data.shape[1] - 2*count), combo)
            count=count-1

但如果我注释掉这两行： self.beginRemoveRows(QModelIndex, start, end) 和来自removeRows方法的self.endRemoveRows()，它有效并且没有更多错误消息。但根据Qt文档，这两个方法必须被调用。

removeRows() 实现必须在调用之前调用 beginRemoveRows() 行从数据结构中删除，并且必须调用 之后立即 endRemoveRows()。

 def removeRows(self, position, rows, QModelIndex):
                start, end = position, rows 
                #self.beginRemoveRows(QModelIndex, start, end) # remove
                self._data.drop(position,inplace=True)
                self._data.reset_index(drop=True,inplace=True)
                #self.endRemoveRows() # remove
                self.layoutChanged.emit()
                return True

我已经尝试了几个小时，但我无法弄清楚这一点。谁能帮我解释一下我的代码有什么问题吗？

这是我的表模型类：

from PyQt5 import QtCore
from PyQt5.QtCore import Qt
from datetime import datetime
import pandas as pd


class TableModel(QtCore.QAbstractTableModel):
    def __init__(self, data):
        super().__init__()
        self._data = data

    def data(self, index, role):
        if role == Qt.DisplayRole or role == Qt.EditRole:
            # See below for the nested-list data structure.
            # .row() indexes into the outer list,
            # .column() indexes into the sub-list
            print(index.row(), index.column())
            value = self._data.iloc[index.row(), index.column()]
            
            # Perform per-type checks and render accordingly.
            if isinstance(value, datetime):
            # Render time to YYY-MM-DD.
                if pd.isnull(value):
                    value=datetime.min
                return value.strftime("%Y-%m-%d")

            if isinstance(value, float):
            # Render float to 2 dp
                return "%.2f" % value

            if isinstance(value, str):
            # Render strings with quotes
                # return '"%s"' % value
                return value

            # Default (anything not captured above: e.g. int)
            return value

    # implement rowCount
    def rowCount(self, index):
        # The length of the outer list.
        return self._data.shape[0]
    
    # implement columnCount
    def columnCount(self, index):
        # The following takes the first sub-list, and returns
        # the length (only works if all rows are an equal length)
        return self._data.shape[1]
    
    # implement flags
    def flags(self, index):
        return Qt.ItemIsSelectable | Qt.ItemIsEnabled | Qt.ItemIsEditable

    # implement setData
    def setData(self, index, value, role):
        if role == Qt.EditRole:
            self._data.iloc[index.row(), index.column()] = value
            # self._data.iat[index.row(), self._data.shape[1]-1] = value
            self.dataChanged.emit(index, index)
            return True

    def headerData(self, section, orientation, role):
        if role == Qt.DisplayRole:
            if orientation == Qt.Horizontal:
                return str(self._data.columns[section])
            if orientation == Qt.Vertical:
                return str(self._data.index[section])
            
    
    def insertRows(self, position, rows, QModelIndex, parent):
        self.beginInsertRows(QModelIndex, position, position+rows-1)
        default_row=[[None] for _ in range(self._data.shape[1])]
        new_df=pd.DataFrame(dict(zip(list(self._data.columns),default_row)))
        self._data=pd.concat([self._data,new_df])
        self._data=self._data.reset_index(drop=True)
        self.endInsertRows()
        self.layoutChanged.emit()
        return True

    def removeRows(self, position, rows, QModelIndex):
        start, end = position, rows 
        self.beginRemoveRows(QModelIndex, start, end) # if remove these 02 lines, it works
        self._data.drop(position,inplace=True)
        self._data.reset_index(drop=True,inplace=True)
        self.endRemoveRows() # if remove these 02 lines, it works
        self.layoutChanged.emit()
        return True

可检查组合框的类：

from PyQt5.QtWidgets import  QComboBox
from PyQt5.QtCore import Qt
import CONSTANT

class CheckableComboBox(QComboBox):
    def __init__(self,item_list, df,number,type,col_offset_value):
        super().__init__()
        self._changed = False
        self.view().pressed.connect(self.handleItemPressed)
        self.view().pressed.connect(self.set_df_value)
        # Store checked item
        self.checked_item=[]
        self.checked_item_index=[]
        self.type=type
        self.col_offset_value=col_offset_value
        
        # DataFrame to be modified
        self.df=df
        # Order number of the combobox
        self.number=number
        
        for i in range(len(item_list)):
            self.addItem(item_list[i])
            self.setItemChecked(i, False)
        # self.activated.connect(self.set_df_value)
            
    def set_df_value(self):
        print(self.number)
        self.df.iat[self.number,self.df.shape[1]-self.col_offset_value*2+1]=','.join(self.checked_item)
        print(self.df)

    def setItemChecked(self, index, checked=False):
        item = self.model().item(index, self.modelColumn())  # QStandardItem object

        if checked:
            item.setCheckState(Qt.Checked)

        else:
            item.setCheckState(Qt.Unchecked)
            
    def set_item_checked_from_list(self,checked_item_index_list):
        for i in range(self.count()):
            item = self.model().item(i, 0)
            if i in checked_item_index_list:
                item.setCheckState(Qt.Checked)
            else:
                item.setCheckState(Qt.Unchecked)
                
    
    def get_item_checked_from_list(self,checked_item_index_list):
        self.checked_item.clear()
        self.checked_item.extend(checked_item_index_list)
    
            
    def handleItemPressed(self, index):
        item = self.model().itemFromIndex(index)

        if item.checkState() == Qt.Checked:
            item.setCheckState(Qt.Unchecked)
            if item.text() in self.checked_item:
                self.checked_item.remove(item.text())
                self.checked_item_index.remove(index.row())
            print(self.checked_item)
            print(self.checked_item_index)

        else:
            
            if item.text()!=CONSTANT.ALL \
                and CONSTANT.ALL not in self.checked_item \
                and item.text()!=CONSTANT.GWP \
                and CONSTANT.GWP not in self.checked_item \
                and item.text()!=CONSTANT.NO_ALLOCATION \
                and CONSTANT.NO_ALLOCATION not in self.checked_item :
                item.setCheckState(Qt.Checked)
                self.checked_item.append(item.text())
                self.checked_item_index.append(index.row())
                print(self.checked_item)
                print(self.checked_item_index)

            else:
                self.checked_item.clear()
                self.checked_item_index.clear()
                self.checked_item.append(item.text())
                self.checked_item_index.append(index.row())
                self.set_item_checked_from_list(self.checked_item_index)


        self._changed = True
        
        self.check_items()

    def hidePopup(self):
        if not self._changed:
            super().hidePopup()
        self._changed = False


    def item_checked(self, index):
        # getting item at index
        item = self.model().item(index, 0)
        # return true if checked else false
        return item.checkState() == Qt.Checked
    
    def check_items(self):
        # traversing the items
        checkedItems=[]
        for i in range(self.count()):
            # if item is checked add it to the list
            if self.item_checked(i):
                checkedItems.append(self.model().item(i, 0).text())

主类：

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import Qt,QDate,QThread
from net_comm_ui import Ui_MainWindow
from PyQt5.QtWidgets import QApplication, QMainWindow
from pathlib import Path
import multiprocessing
from  TableModel import TableModel
from CheckableComboBox import CheckableComboBox
import copy
import datetime
import re
import json
from pathlib import Path
import pandas as pd
import os
from net_comm_worker import Worker
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
from PyQt5.QtCore import pyqtSlot

dept_list = ['A','B','C','D','E','F','G','H']
combo_type=['METHOD','LOB','DEPT','CHANNEL']


class MainWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self.tableView = QtWidgets.QTableView()
        import pandas as pd
    
        
        mydict = [{'a': 1, 'b': 2, 'c': 3, 'd': 4},
          {'a': 100, 'b': 200, 'c': 300, 'd': 400},
          {'a': 1000, 'b': 2000, 'c': 3000, 'd': 4000 }]
        
        self.data=pd.DataFrame(mydict)
        
        print('initial self.data')
        print(self.data)
        
        self.data['Allocation Method'] = ''
        self.data['Allocation Method Selected']=''
        self.data['Allocation LOB'] = ''
        self.data['Allocation LOB Selected']=''
        self.data['Allocation DEPT'] = ''
        self.data['Allocation DEPT Selected']=''
        self.data['Allocation CHANNEL'] = ''
        self.data['Allocation CHANNEL Selected']=''
        

        self.model = TableModel(self.data)
        self.tableView.setModel(self.model)
        self.setCentralWidget(self.tableView)
        self.setGeometry(600, 200, 500, 300)
        
        count=len(combo_type)
        # Set ComboBox to cells
        for type in combo_type:
            for row_num in range(self.model._data.shape[0]):
                # print(i)
                combo = CheckableComboBox(dept_list,self.model._data,row_num,type,count)
                self.tableView.setIndexWidget(self.model.index(row_num, self.model._data.shape[1] - 2*count), combo)
            count=count-1
        
        button = QPushButton('Delete row', self)
        button.move(100,200)
        button.clicked.connect(self.delete_row)
        
 
    def delete_row(self):
        index = self.tableView.currentIndex()
        if index.row()<self.model._data.shape[0]:
            self.model.removeRows(index.row(), 1, index)
            print('self.model._data')
            print(self.model._data)
            print('self.data')
            print(self.data)



app = QtWidgets.QApplication(sys.argv)
window = MainWindow()
window.show()
app.exec_()

我添加一种方法来添加行。 self.layoutChanged.emit() 是否必须更新 TableView 还是有更有效的方法？：

def insertRows(self, position, rows, QModelIndex, parent):
    self.beginInsertRows(QModelIndex, position, position+rows-1)
    default_row=[[None] for _ in range(self._data.shape[1])]
    new_df=pd.DataFrame(dict(zip(list(self._data.columns),default_row)))
    self._data=pd.concat([self._data,new_df])
    self._data.reset_index(drop=True, inplace=True)
    self.endInsertRows()
    self.layoutChanged.emit() # ==> is this mandatory?
    return True

Answer 1

您的示例将错误的索引传递给 removeRows，这也无法正确计算开始值和结束值。可以这样修复：

class MainWindow(QtWidgets.QMainWindow):
    ...
    def delete_row(self):
        index = self.tableView.currentIndex()
        self.model.removeRows(index.row(), 1)

    def insert_row(self):
        self.model.insertRows(self.model.rowCount(), 1)

class TableModel(QtCore.QAbstractTableModel):
    ...
    def rowCount(self, parent=QModelIndex()):
        ...

    def columnCount(self, parent=QModelIndex()):
        ...

    def insertRows(self, position, rows, parent=QModelIndex()):
        start, end = position, position + rows - 1
        if 0 <= start <= end:
            self.beginInsertRows(parent, start, end)
            for index in range(start, end + 1):
                default_row = [[None] for _ in range(self._data.shape[1])]
                new_df = pd.DataFrame(dict(zip(list(self._data.columns), default_row)))
                self._data = pd.concat([self._data, new_df])
            self._data = self._data.reset_index(drop=True)
            self.endInsertRows()
            return True
        return False

    def removeRows(self, position, rows, parent=QModelIndex()):
        start, end = position, position + rows - 1
        if 0 <= start <= end and end < self.rowCount(parent):
            self.beginRemoveRows(parent, start, end)
            for index in range(start, end + 1):
                self._data.drop(index, inplace=True)
            self._data.reset_index(drop=True, inplace=True)
            self.endRemoveRows()
            return True
        return False