sorting.py

class MyTableWidgetItem(QtWidgets.QTableWidgetItem):
    def __init__(self, parent=None):
        QtWidgets.QTableWidgetItem.__init__(self, parent)

    def __lt__(self, otherItem):
        try:
            return int(self.text().split('-')[0]) < int(otherItem.text().split('-')[0])
        except ValueError:
            return self.text() < otherItem.text()
          

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    mywidget = QtWidgets.QTableWidget()
    mywidget.insertColumn(0)

    list = ["1", "2", "10", "11", "14-15", "120", "100-115", "59-62"]
    for index in range(len(list)):
        mywidget.insertRow(index)
        value = list[index]
        item = MyTableWidgetItem(value)
        mywidget.setItem(index, 0, item)

    mywidget.sortItems(0, QtCore.Qt.AscendingOrder)
    mywidget.show()
    sys.exit(app.exec_())