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I'm following the cookbook tutorial on evaluating expressions. QGIS 3.16 using the in-built python editor. I've initiated the context scope in the variable context as per the tutorial. The rest is test code ultimately aiming at updating the double field Rain_D using the contents of the string field Rainfall

# Calculate Rain_D values

context = QgsExpressionContext()
context.appendScopes(QgsExpressionContextUtils.globalProjectLayerScopes(weather_l))


n = 0
with edit(weather_l):
    for fea in weather_l.getFeatures():
        n += 1
        context.setFeature(fea)
        if fea['Rainfall'].isalpha():
            print(n)
        weather_l.updateFeature(fea)

The problem is that when the for loop gets to about a thousand or so iterations (it's different every time) QGIS crashes. Any idea what's going on here? It works if I break after a few iterations, but not when going through the 100,000 or so records in weather_l.

PolyGeo
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GlenS
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  • This looks like a bug report. Have you considered creating an issue to inform QGIS devs? You can do so at https://github.com/qgis/QGIS/issues/ BTW, you can find some alternatives in this answer. – Germán Carrillo Aug 20 '21 at 01:45
  • I thought it was possibly a bug but I'm new at pyqgis so I wanted to check first. I'll submit it. Thanks. – GlenS Aug 20 '21 at 01:54

0 Answers0