I want to sum up an entire column in a QTableWidget

Question

I'm creating a spreadsheet in PyQt5 and I'm trying to add mathematical functionality. Is there a way to sum up the contents of an entire column either by calling the column Horizontal Header Label or the number of the column?

For example, how would I sum up the contents of the 'Gas' column from this QTableWidget below?

Answer 1

You have to use itemChanged which is emitted when a QTableWidgetItem changes.

import random
import sys

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import (
    QApplication,
    QMainWindow,
    QSpinBox,
    QStyledItemDelegate,
    QTableWidget,
    QTableWidgetItem,
)

COLUMN = 2


class Delegate(QStyledItemDelegate):
    def createEditor(self, parent, option, index):
        return QSpinBox(parent=parent, minimum=0, maximum=1000)


class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)

        self.table = QTableWidget(10, 10)
        self.table.itemChanged.connect(self.handle_item_changed)
        delegate = Delegate(self.table)
        self.table.setItemDelegateForColumn(COLUMN, delegate)
        self.table.setHorizontalHeaderItem(COLUMN, QTableWidgetItem("Gas"))

        for i in range(5):
            value = random.randint(3, 10)
            item = QTableWidgetItem()
            item.setData(Qt.DisplayRole, value)
            self.table.setItem(i, COLUMN, item)

        self.setCentralWidget(self.table)

    def handle_item_changed(self, item):
        if item.column() == COLUMN:
            r = 0
            for i in range(self.table.rowCount()):
                item = self.table.item(i, COLUMN)
                if item:
                    value = item.data(Qt.DisplayRole)
                    if isinstance(value, int):
                        r += value
            print(f"sum = {r}")


def main():
    app = QApplication(sys.argv)
    view = MainWindow()
    view.resize(640, 480)
    view.show()
    sys.exit(app.exec_())


if __name__ == "__main__":
    main()