[SOLVED] Pyside qtreewidget numeric sorting

sharky · 04-19-2014, 07:04 PM

Is there a way to get a column in a QTreeWidget to sort numerically? I have search the interweb for solutions and have not been able to get anything to work.

Tried converting the data to integer prior to populating the tree and the data would not even populate. Got no errors from this - just empty spaces in the tree.

I am open to comments, advice, or suggestions.

Using python 2.7 and Qt 4.8

Cheers,

sharky · 04-21-2014, 02:17 PM

I found a solution but I don't really understand how it works. Pretty much did a cut and paste.

Code:

# re-implement the QTreeWidgetItem
class TreeWidgetItem(QTreeWidgetItem):
    def __lt__(self, other):
        column = self.treeWidget().sortColumn()
        key1 = self.text(column)
        key2 = other.text(column)
        return self.natural_sort_key(key1) < self.natural_sort_key(key2)

    @staticmethod
    def natural_sort_key(key):
        regex = '(\d*\.\d+|\d+)'
        parts = re.split(regex, key)
        return tuple((e if i % 2 == 0 else float(e)) for i, e in enumerate(parts))

Also had to 'import re' and the part of my code where I populate the tree I replace 'QTreeWidgetItem' with the new class, "TreeWidgetItem".

I'm definitely am confused but it works and that's what I need.

If you can explain this then please feel free to do so.

Cheers,

dugan · 04-21-2014, 04:20 PM

Here's an example that follows current PyQt best practices. It uses a QStandardItemModel+QtreeView combination, instead of a QTreeWidget. Sorting is done with a QSortFilterProxyModel subclass.

Code:

#!/usr/bin/env python

from sip import setapi
setapi("QDate", 2)
setapi("QDateTime", 2)
setapi("QTextStream", 2)
setapi("QTime", 2)
setapi("QVariant", 2)
setapi("QString", 2)
setapi("QUrl", 2)


from PyQt4.QtCore import Qt
from PyQt4.QtGui import (QApplication, QMainWindow, QStandardItem,
                         QSortFilterProxyModel, QStandardItemModel, QTreeView)
import sys


def main():

    app = QApplication(sys.argv)
    view = TreeView()
    view.show()
    sys.exit(app.exec_())


class TreeView(QMainWindow):

    def __init__(self, parent=None):
        super(TreeView, self).__init__(parent)

        treeModel = QStandardItemModel(self)

        treeModel.appendRow(self._createRow('cc', '14', '2'))
        treeModel.appendRow(self._createRow('bb', '5', '1'))
        treeModel.appendRow(self._createRow('dd', '3', '14'))

        proxyModel = ProxyModel(self)
        proxyModel.setSourceModel(treeModel)

        treeView = QTreeView()
        treeView.setSortingEnabled(True)
        treeView.setModel(proxyModel)
        self.setCentralWidget(treeView)

    @classmethod
    def _createRow(cls, *args):
        return [cls._createItem(value) for value in args]

    @staticmethod
    def _createItem(data):
        item = QStandardItem(data)
        flags = item.flags()
        flags ^= Qt.ItemIsEditable
        item.setFlags(flags)
        return item


class ProxyModel(QSortFilterProxyModel):

    def __init__(self, parent=None):
        super(ProxyModel, self).__init__(parent)

    def lessThan(self, left, right):
        leftData = self.sourceModel().data(left)
        rightData = self.sourceModel().data(right)

        try:
            return int(leftData) < int(rightData)
        except ValueError:
            return leftData < rightData

if __name__ == '__main__':
    main()

Click the header on each column, and the column will be sorted in numerical (not lexical) order.

See, especially:

http://qt-project.org/doc/qt-4.8/qso...l.html#sorting

The solution that you found is a tremendously ugly hack that monkey-patches QTreeWidgetItem and overrides its __lt__ method. The __lt__ method is called by the implementation of the comparison operator, "<", and the comparison operator is presumably called by the QTreeWidget's internal sorting routines. And as far as I can tell, its natural_sort_key method (which has the "re" dependency) can be eliminated and replaced with float with the same effect. So:

Code:

# re-implement the QTreeWidgetItem
class TreeWidgetItem(QTreeWidgetItem):
    def __lt__(self, other):
        column = self.treeWidget().sortColumn()
        key1 = self.text(column)
        key2 = other.text(column)
        return float(key1) < float(key2)

sharky · 04-21-2014, 07:11 PM

Hi Dugan,
Your example returned a syntax error on line 47. I am not able to fix it.

With respect to using float instead of the natural_sort_key doesn't work on text. My first column is text and then the next two columns are integers. So column one needs alphbetical sorting and columns two and three need numerical sorting.

dugan · 04-21-2014, 07:23 PM

I've fixed the example. The syntax error on line 47 is gone, and there is now a sortable left column of text, in addition to two sortable columns of numbers.

And as for the example you found, here's a revision that will work with both text and numbers:

Code:

# re-implement the QTreeWidgetItem
class TreeWidgetItem(QTreeWidgetItem):
    def __lt__(self, other):
        column = self.treeWidget().sortColumn()
        key1 = self.text(column)
        key2 = other.text(column)
        try:
            return float(key1) < float(key2)
        except ValueError:
            return key1 < key2

sharky · 04-22-2014, 01:43 PM

Mr. Dugan, Thanks again for your help. For now I am using your revision of my 'ugly hack'.