Save output as CSV QGIS 3

Question

I am trying to save the result of a distance matrix on two layers in CSV (or in shapefile could be okay as well)

You will find the code used for the distance matrix on below:

sLayerName = "Centroids_site"
tLayerName = "Centroids_lotiss"
sLayers = QgsProject.instance().mapLayersByName(sLayerName)
sLayer = sLayers[0]
# Distance between all features from two different layers
tLayers = QgsProject.instance().mapLayersByName(tLayerName)
tLayer = tLayers[0]
sFeats = sLayer.getFeatures()
print(sLayer.featureCount())
for sfeat in sFeats:
 sgeom = sfeat.geometry()
 tFeats = tLayer.getFeatures()
 for tfeat in tFeats:
 tgeom = tfeat.geometry()
 dist_pl = sgeom.distance(tgeom)
 print(sfeat.id(), tfeat.id(), dist_pl)
 print(sfeat.id(), 'done')

I have the output on console, but I would like to have it in a file (CSV, preferentially)

The code for the distance matrix come from "OpenSourceOptions" https://opensourceoptions.com/blog/pyqgis-measure-the-distance-between-geometries/

• Ben W: realpython.com/python-csv/#writing-csv-files-with-csv
• M Dollinger: From gis.stackexchange.com/questions/373784/… QgsVectorFileWriter.writeAsVectorFormat(your_layer, Your_path_and_filename, "utf-8", driverName = "CSV" , layerOptions = ['GEOMETRY=AS_XYZ'])

Answer 1

Thanks to the code given by @MDollinger & @BenW I have succeeded to save the output in csv, but first I had to create a virtual layer (see: https://gis.stackexchange.com/a/437794/172081). The final code become:

sLayerName = "Centroids_site"
tLayerName = "Centroids_lotiss"
sLayer = QgsProject.instance().mapLayersByName(sLayerName)[0]
tLayer = QgsProject.instance().mapLayersByName(tLayerName)[0]
# make new memory layer
dist_layer = QgsVectorLayer("None?field=sid:integer&field=tid:integer&field=dist:double", "dist", "memory")
dist_layer.startEditing()
for sfeat in sLayer.getFeatures():
 sgeom = sfeat.geometry()
 for tfeat in tLayer.getFeatures():
 dist_pl = sfeat.geometry().distance(tfeat.geometry())
 
 # make new feature
 feat = QgsFeature(dist_layer.fields())
 feat["sid"] = sfeat.id()
 feat["tid"] = tfeat.id()
 feat["dist"] = dist_pl
 
 # add the feature to the table
 dist_layer.addFeature(feat)
dist_layer.commitChanges()
QgsProject.instance().addMapLayer(dist_layer)
QgsVectorFileWriter.writeAsVectorFormat(dist_layer, "/Users/Me/Downloads/dist.csv", "utf-8", driverName = "CSV" , layerOptions = ['GEOMETRY=AS_XYZ'])