Qtablewidget Display Certain Decimals Like Excel

My question is about the way the QTableWidget displays the cell values. I'd like for the cell to show only three decimals when it's not being edited and show the full value when yo

Solution 1:

The solution is to use a delegate and override the paint method that is responsible for showing what looks in normal state, I have built the following class based on the above.

classFloatDelegate(QItemDelegate):
    def__init__(self, decimals, parent=None):
        QItemDelegate.__init__(self, parent=parent)
        self.nDecimals = decimals

    defpaint(self, painter, option, index):
        value = index.model().data(index, Qt.EditRole)
        try:
            number = float(value)
            painter.drawText(option.rect, Qt.AlignLeft, "{:.{}f}".format(number, self.nDecimals))
        except :
            QItemDelegate.paint(self, painter, option, index)

In your case you should use it as follows:

self.TableWidget.setItemDelegate(FloatDelegate(3))

Example:

if__name__== '__main__':
    importsysapp= QApplication(sys.argv)
    w = QTableWidget()
    w.setColumnCount(8)
    w.setRowCount(8)
    for i in range(w.rowCount()):
        for j in range(w.columnCount()):
            number = (i+1)/(j+1)
            w.setItem(i, j, QTableWidgetItem(str(number)))
    w.setItemDelegate(FloatDelegate(3, w))
    w.show()
    sys.exit(app.exec_())

Screenshots:

Plus:

By Row o Column:

#only column 2setItemDelegateForColumn(2, FloatDelegate(3))
#only row 2setItemDelegateForRow(2, FloatDelegate(3))

If you want to apply only to cell 2,3

defpaint(self, painter, option, index):
   if index.row() == 2and index.column() == 3:
        value = index.model().data(index, Qt.EditRole)
        try:
            number = float(value)
            painter.drawText(option.rect, Qt.AlignLeft, "{:.{}f}".format(number, self.nDecimals))
        except :
            QItemDelegate.paint(self, painter, option, index)
    else:
        QItemDelegate.paint(self, painter, option, index)

Update:

• QStyledItemDelegate:

  from math import log10
  
  classFloatDelegate(QStyledItemDelegate):
      def__init__(self, decimals, parent=None):
          super(FloatDelegate, self).__init__(parent=parent)
          self.nDecimals = decimals
  
      defdisplayText(self, value, locale):
          try:
              number = float(value)
          except ValueError:
              returnsuper(FloatDelegate, self).displayText(value, locale)
          else:
              precision = log10(number) + 1 + self.nDecimals
              return locale.toString(number, f='f', prec=precision)