[Qgis-developer] Select By Attribute

[Denis Rouzaud]

On 27. 02. 14 18:41, Michael McInnis wrote:
> Desperately need help doing attribute based selection :
>
>
> How do I select all features in a LAYER that the Field LWFLAG != 'P'
>
> Python Console
>
>
> from osgeo import ogr
>
> canvas = qgis.utils.iface.mapCanvas()
>
> allLayers = canvas.layers()
>
> for i in allLayers: i.selectAll(); print i.name(); print 
> i.selectedFeatureCount()
>
> for i in allLayers: i.selectAll(); print i.name(); print 
> i.selectedFeatureCount()
>
> i.getFeatures(QgsFeatureRequest().setFilterExpression(' "LWFLAGS" != 
> \'P\') )
>
this is a feature iterator [0], so you need iterate

f = QgsFeature()
toSelect = []
while i.getFeatures(QgsFeatureRequest().setFilterExpression(' "LWFLAGS" 
!= \'P\') ).nextFeature(f):
     toSelect.append(f.id())
i.setSelectedFeatures(toSelect)

[0] http://qgis.org/api/classQgsFeatureIterator.html

> exp = QgsExpression('LWFLAG <> "P" ')
>
>
>
>
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