title: how to edit specific item in qtableview?
body: <p>Is there a way to edit specific item in qtableview given the row and col value? For example, I want to increment its value every second. Here is my tablemodel. Thanks</p>
  
  <pre><code>class MyTableModel(QAbstractTableModel):
  
      def __init__(self, datain, headerdata, parent=None, *args): 
          """ datain: a list of lists
              headerdata: a list of strings
          """
          QAbstractTableModel.__init__(self, parent, *args) 
          self.arraydata = datain
          self.headerdata = headerdata
  
  
      def rowCount(self, parent):
          return len(self.arraydata) 
  
      def columnCount(self, parent):
          try:
              return len(self.arraydata[0]) 
          except:
              return 0
      def data(self, index, role): 
          if not index.isValid():
              return QVariant() 
          elif role != Qt.DisplayRole:
              return QVariant() 
          return QVariant(self.arraydata[index.row()][index.column()]) 
  
      def headerData(self, col, orientation, role):
  
          if orientation == Qt.Horizontal and role == Qt.DisplayRole:
                  return QVariant(self.headerdata[col])
          return QVariant()
  
      def sort(self, Ncol, order):
          """Sort table by given column number.
          """
          self.emit(SIGNAL("layoutAboutToBeChanged()"))
          self.arraydata = sorted(self.arraydata, key=operator.itemgetter(Ncol))        
          if order == Qt.DescendingOrder:
              self.arraydata.reverse()
          self.emit(SIGNAL("layoutChanged()"))
  </code></pre>