Merge pull request #7363 from alexbruy/fix-sampling

[processing] fix Random extract/select within subset algorithms
qgis · Jul 4, 2018 · 6d751dc · 6d751dc
2 parents 6c014b4 + b72f5d1
commit 6d751dc
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Showing 3 changed files with 24 additions and 2 deletions.
diff --git a/python/plugins/processing/algs/qgis/RandomExtractWithinSubsets.py b/python/plugins/processing/algs/qgis/RandomExtractWithinSubsets.py
@@ -125,8 +125,11 @@ def processAlgorithm(self, parameters, context, feedback):
             classes[attrs[index]].append(feature)
             feedback.setProgress(int(i * total))
 
-        for subset in classes.values():
+        for k, subset in classes.items():
             selValue = value if method != 1 else int(round(value * len(subset), 0))
+            if selValue > len(subset):
+                selValue = len(subset)
+                feedback.reportError(self.tr('Subset "{}" is smaller than requested number of features.'.format(k)))
             selran.extend(random.sample(subset, selValue))
 
         total = 100.0 / featureCount if featureCount else 1

diff --git a/python/plugins/processing/algs/qgis/RandomSelectionWithinSubsets.py b/python/plugins/processing/algs/qgis/RandomSelectionWithinSubsets.py
@@ -133,11 +133,14 @@ def processAlgorithm(self, parameters, context, feedback):
                 feedback.setProgress(int(i * total))
 
             selran = []
-            for subset in classes.values():
+            for k, subset in classes.items():
                 if feedback.isCanceled():
                     break
 
                 selValue = value if method != 1 else int(round(value * len(subset), 0))
+                if selValue > len(subset):
+                    selValue = len(subset)
+                    feedback.reportError(self.tr('Subset "{}" is smaller than requested number of features.'.format(k)))
                 selran.extend(random.sample(subset, selValue))
 
             layer.selectByIds(selran)

diff --git a/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml b/python/plugins/processing/tests/testdata/qgis_algorithm_tests.yaml
@@ -3923,6 +3923,21 @@ tests:
         name: points_weighted.gml
         compare: false
 
+  - algorithm: qgis:randomextractwithinsubsets
+    name: Random extract within subset (subset smaller than number)
+    params:
+      FIELD: id2
+      INPUT:
+        name: points.gml
+        type: vector
+      METHOD: 0
+      NUMBER: 3
+    results:
+      OUTPUT:
+        type: vector
+        name: points.gml
+        compare: false
+
   - algorithm: qgis:heatmapkerneldensityestimation
     name: Heatmap (Kernel density estimation)
     params:
@@ -5355,6 +5370,7 @@ tests:
         compare:
           fields:
             fid: skip
+
   - algorithm: native:difference
     name: Test Difference B - A (basic)
     params: