QGIS equivalent to arcpy.SearchCursor?

Question

What is the equivalent in QGIS (or other FOSS) to this:

rows = arcpy.SearchCursor(table,
                          fields="ORIG_FID; field1; field2; field3; field4",
                          sort_fields="ORIG_FID A")

for row in rows:

http://gis.stackexchange.com/questions/24849/how-to-translate-esri-cursor-example-to-pyqgis — user7172, Mar 10 '16 at 14:01

score 5 · Accepted Answer · edited Apr 13 '17 at 12:33

5

Check out the PyQGIS Cookbook's section on Using Vector Layers.

Hacking together the examples there:

# The expression will filter the features where the field "location_name" contains
# the word "Lake" (case insensitive)
exp = QgsExpression('location_name ILIKE \'%Lake%\'')
request = QgsFeatureRequest(exp)
request.setSubsetOfAttributes(['name','id'],layer.pendingFields())
for feature in layer.getFeatures(request):
    # do whatever you need with the feature

Also, see this question for some other hints: What are QGIS Arcpy Equivalent Functions for Update/Delete Row/Field?

edited Apr 13 '17 at 12:33

Community

1

answered Mar 10 '16 at 12:44

Richard Morgan

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Thank you Richard, I'll check this approach! Although at first sight I don't see the "sort fields" option. – Albert Mar 11 '16 at 07:15
1

@Albert As a newbie, I am also not seeing where in the Cookbook they show examples of the sort. However, I did find this answer: http://gis.stackexchange.com/q/138769/43 – Richard Morgan Mar 11 '16 at 13:01

score 2 · Answer 2 · edited Sep 22 '20 at 13:44

2

Use .getFeatures(), this returns all layer field values:

Query the provider for features specified in request.

for feature in table.getFeatures():
    if feature['myField'] == someVariable:
        # do something

edited Sep 22 '20 at 13:44

Aaron

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answered Mar 10 '16 at 12:38

artwork21

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QGIS equivalent to arcpy.SearchCursor?

2 Answers2