Restore frequency analysis script

This script has been changed to use a sink output, not the previous TableWriter csv output. All algorithms which output flat tables should now still output feature sinks, to allow correct use in later model steps.
qgis · Jun 26, 2017 · 86d33c1 · 86d33c1
1 parent d49114c
commit 86d33c1
Showing 1 changed file with 22 additions and 12 deletions.
diff --git a/python/plugins/processing/algs/qgis/scripts/Frequency_analysis.py b/python/plugins/processing/algs/qgis/scripts/Frequency_analysis.py
@@ -3,37 +3,47 @@
 #inputs
 
 ##Input=source
-##Fields=field Input
-##Frequency=output table
+##Fields=field multiple Input
+##Frequency=sink table
 
 #outputs
-
+##Frequency=output outputVector
 
 from processing.tools.vector import TableWriter
 from collections import defaultdict
-from qgis.core import QgsProcessingUtils
+from qgis.core import QgsProcessingUtils, QgsFields, QgsField, QgsWkbTypes, QgsFeature
+from qgis.PyQt.QtCore import QVariant
 from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
 
-layer = QgsProcessingUtils.mapLayerFromString(Input, context)
-inputFields = layer.fields()
+inputFields = Input.fields()
 fieldIdxs = []
-fields = Fields.split(',')
-for f in fields:
+out_fields = QgsFields()
+for f in Fields:
     idx = inputFields.indexFromName(f)
     if idx == -1:
         raise GeoAlgorithmExecutionException('Field not found:' + f)
     fieldIdxs.append(idx)
-writer = TableWriter(Frequency, None, fields + ['FREQ'])
+    out_fields.append(inputFields.at(idx))
+
+out_fields.append(QgsField('FREQ', QVariant.Int))
+
+(sink, Frequency) = self.parameterAsSink(parameters, 'Frequency', context,
+                                         out_fields)
 
 counts = {}
-feats = QgsProcessingUtils.getFeatures(layer, context)
-nFeats = QgsProcessingUtils.featureCount(layer, context)
+feats = Input.getFeatures()
+nFeats = Input.featureCount()
 counts = defaultdict(int)
 for i, feat in enumerate(feats):
     feedback.setProgress(int(100 * i / nFeats))
+    if feedback.isCanceled():
+        break
+
     attrs = feat.attributes()
     clazz = tuple([attrs[i] for i in fieldIdxs])
     counts[clazz] += 1
 
 for c in counts:
-    writer.addRecord(list(c) + [counts[c]])
+    f = QgsFeature()
+    f.setAttributes(list(c) + [counts[c]])
+    sink.addFeature(f)