Fix inefficient calls to QgsFeature.attributes()[idx]

nyalldawson · nyalldawson · commit ef1cf0940194 · 2018-10-31T09:58:17.000+10:00
Replace with just f[idx]. Calling QgsFeature.attributes() allocates a list of all attributes, which is inefficient when only a single attribute value is needed. (cherry picked from commit 85efc77)
diff --git a/python/plugins/processing/algs/qgis/MinimumBoundingGeometry.py b/python/plugins/processing/algs/qgis/MinimumBoundingGeometry.py
@@ -162,15 +162,15 @@ def processAlgorithm(self, parameters, context, feedback):
 
                 if type == 0:
                     # bounding boxes - calculate on the fly for efficiency
-                    if not f.attributes()[field_index] in bounds_dict:
-                        bounds_dict[f.attributes()[field_index]] = f.geometry().boundingBox()
+                    if not f[field_index] in bounds_dict:
+                        bounds_dict[f[field_index]] = f.geometry().boundingBox()
                     else:
-                        bounds_dict[f.attributes()[field_index]].combineExtentWith(f.geometry().boundingBox())
+                        bounds_dict[f[field_index]].combineExtentWith(f.geometry().boundingBox())
                 else:
-                    if not f.attributes()[field_index] in geometry_dict:
-                        geometry_dict[f.attributes()[field_index]] = [f.geometry()]
+                    if not f[field_index] in geometry_dict:
+                        geometry_dict[f[field_index]] = [f.geometry()]
                     else:
-                        geometry_dict[f.attributes()[field_index]].append(f.geometry())
+                        geometry_dict[f[field_index]].append(f.geometry())
 
                 feedback.setProgress(int(current * total))
 
diff --git a/python/plugins/processing/algs/qgis/PointDistance.py b/python/plugins/processing/algs/qgis/PointDistance.py
@@ -187,7 +187,7 @@ def linearMatrix(self, parameters, context, source, inField, target_source, targ
                 break
 
             inGeom = inFeat.geometry()
-            inID = str(inFeat.attributes()[inIdx])
+            inID = str(inFeat[inIdx])
             featList = index.nearestNeighbor(inGeom.asPoint(), nPoints)
             distList = []
             vari = 0.0
@@ -199,7 +199,7 @@ def linearMatrix(self, parameters, context, source, inField, target_source, targ
                 if same_source_and_target and inFeat.id() == outFeat.id():
                     continue
 
-                outID = outFeat.attributes()[outIdx]
+                outID = outFeat[outIdx]
                 outGeom = outFeat.geometry()
                 dist = distArea.measureLine(inGeom.asPoint(),
                                             outGeom.asPoint())
diff --git a/python/plugins/processing/algs/qgis/PointsInPolygon.py b/python/plugins/processing/algs/qgis/PointsInPolygon.py
@@ -155,14 +155,14 @@ def processAlgorithm(self, parameters, context, feedback):
 
                     if engine.contains(point_feature.geometry().constGet()):
                         if weight_field_index >= 0:
-                            weight = point_feature.attributes()[weight_field_index]
+                            weight = point_feature[weight_field_index]
                             try:
                                 count += float(weight)
                             except:
                                 # Ignore fields with non-numeric values
                                 pass
                         elif class_field_index >= 0:
-                            point_class = point_feature.attributes()[class_field_index]
+                            point_class = point_feature[class_field_index]
                             if point_class not in classes:
                                 classes.add(point_class)
                         else:
diff --git a/python/plugins/processing/algs/qgis/RandomSelectionWithinSubsets.py b/python/plugins/processing/algs/qgis/RandomSelectionWithinSubsets.py
@@ -129,7 +129,7 @@ def processAlgorithm(self, parameters, context, feedback):
                 if feedback.isCanceled():
                     break
 
-                classes[feature.attributes()[index]].append(feature.id())
+                classes[feature[index]].append(feature.id())
                 feedback.setProgress(int(i * total))
 
             selran = []
diff --git a/python/plugins/processing/algs/qgis/SpatialJoin.py b/python/plugins/processing/algs/qgis/SpatialJoin.py
@@ -234,7 +234,7 @@ def processAlgorithm(self, parameters, context, feedback):
 
                 join_attributes = []
                 for a in join_field_indexes:
-                    join_attributes.append(f.attributes()[a])
+                    join_attributes.append(f[a])
 
                 if engine is None:
                     engine = QgsGeometry.createGeometryEngine(f.geometry().constGet())
diff --git a/python/plugins/processing/algs/qgis/SpatialJoinSummary.py b/python/plugins/processing/algs/qgis/SpatialJoinSummary.py
@@ -306,7 +306,7 @@ def addField(original, stat, type):
 
                 join_attributes = []
                 for a in join_field_indexes:
-                    join_attributes.append(test_feat.attributes()[a])
+                    join_attributes.append(test_feat[a])
 
                 if engine is None:
                     engine = QgsGeometry.createGeometryEngine(f.geometry().constGet())
diff --git a/python/plugins/processing/tools/vector.py b/python/plugins/processing/tools/vector.py
@@ -76,7 +76,7 @@ def values(source, *attributes):
 
             # convert attribute value to number
             try:
-                v = float(feature.attributes()[i])
+                v = float(feature[i])
             except:
                 v = None
 
