Port some more code to new API

Author: nyalldawson

python/plugins/processing/algs/qgis/FieldsMapper.py

@@ -153,8 +153,9 @@ def processAlgorithm(self, context, feedback):
         inFeat = QgsFeature()
         outFeat = QgsFeature()
         features = QgsProcessingUtils.getFeatures(layer, context)
-        if len(features):
-            total = 100.0 / QgsProcessingUtils.featureCount(layer, context)
+        count = QgsProcessingUtils.featureCount(layer, context)
+        if count > 0:
+            total = 100.0 / count
             for current, inFeat in enumerate(features):
                 rownum = current + 1
 

python/plugins/processing/algs/qgis/scripts/Frequency_analysis.py

@@ -5,6 +5,7 @@
 
 from processing.tools.vector import TableWriter
 from collections import defaultdict
+from qgis.core import QgsProcessingUtils
 from processing.core.GeoAlgorithmExecutionException import GeoAlgorithmExecutionException
 from processing.tools import dataobjects
 
@@ -20,8 +21,8 @@
 writer = TableWriter(Frequency, None, fields + ['FREQ'])
 
 counts = {}
-feats = processing.features(layer)
-nFeats = len(feats)
+feats = QgsProcessingUtils.getFeatures(layer, context)
+nFeats = QgsProcessingUtils.featureCount(layer, context)
 counts = defaultdict(int)
 for i, feat in enumerate(feats):
     feedback.setProgress(int(100 * i / nFeats))

python/plugins/processing/algs/qgis/scripts/Keep_n_biggest_parts.py

@@ -5,7 +5,7 @@
 ##Biggest parts=output vector
 
 from processing.tools import dataobjects
-from qgis.core import QgsGeometry, QgsWkbTypes
+from qgis.core import QgsGeometry, QgsWkbTypes, QgsProcessingUtils
 from operator import itemgetter
 
 To_keep = int(To_keep)
@@ -21,7 +21,7 @@
                                  QgsWkbTypes.MultiPolygon, polyPrder.crs())
 
 
-for n, feat in enumerate(processing.features(polyLayer)):
+for n, feat in enumerate(QgsProcessingUtils.getFeatures(polyLayer, context)):
     feedback.setProgress(int(100 * n / count))
     geom = feat.geometry()
     if geom.isMultipart():

python/plugins/processing/algs/qgis/scripts/Number_of_unique_values_in_classes.py

@@ -5,7 +5,7 @@
 ##N_unique_values=output vector
 
 from qgis.PyQt.QtCore import QVariant
-from qgis.core import QgsFeature, QgsField
+from qgis.core import QgsFeature, QgsField, QgsProcessingUtils
 from processing.tools.vector import VectorWriter
 from processing.tools import dataobjects
 
@@ -20,8 +20,8 @@
 
 outFeat = QgsFeature()
 classes = {}
-feats = processing.features(layer)
-nFeat = len(feats)
+feats = QgsProcessingUtils.getFeatures(layer, context)
+nFeat = QgsProcessingUtils.featureCount(layer, context)
 for n, inFeat in enumerate(feats):
     feedback.setProgress(int(100 * n / nFeat))
     attrs = inFeat.attributes()