[PyQt] returning numpy numbers in QVariant
phil at riverbankcomputing.com
Fri Apr 23 13:57:53 BST 2010
On Tue, 20 Apr 2010 22:35:03 +0100, Jeremy Sanders
<jeremy at jeremysanders.net> wrote:
> Hi - some of my code has stopped working after upgrading to PyQt 4.7. It
> seems numbers in numpy arrays used to convert okay to QVariant types, but
> now they seem to produce blank results:
> import sys
> from PyQt4.QtCore import *
> from PyQt4.QtGui import *
> import numpy
> class Model(QAbstractTableModel):
> def columnCount(self, parent):
> return 1
> def rowCount(self, parent):
> return 100
> def data(self, index, role):
> if role == Qt.DisplayRole:
> a = numpy.array([index.row()*0.1])
> return QVariant(a)
> return QVariant()
> if __name__ == "__main__":
> app = QApplication(sys.argv)
> win = QTableView()
> mod = Model()
> This should show a list of numbers in the QTableView. It did and does not
> any longer.
> Is this a bug or shouldn't I be doing this?
Are numpy numbers regular ints/floats or are they a sub-class specific to
QVariant has been changed (over time) to make sure that no information is
lost when converting from and to the original object. So an int sub-class
will stay as a Python object and will not get converted to a C++ int.
If this is the problem then the fix is to explicitly convert the numpy
number to a base Python type before converting to a QVariant...
...and this will work for older versions as well.
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