Add fields from a feature to a feature in another layer

Question

I have a criteria to select the features from a layer that overlap the features of another layer, but i do not know how to copy the fields at the same time: Tyhe code does: - two layers (1 and 2) of polygons - if one feature of polygon2 overlap more than 80% one of polygon1, it selects it.

How to also copy the fields of polygon1 to add them to the fields of the selected polygon2?

from qgis.core import *
import processing
import os

mapcanvas = iface.mapCanvas()

layers = mapcanvas.layers()

#polygon1
feats_lyr1 = [ feat for feat in layers[0].getFeatures() ]

#polygon2
feats_lyr2 = [ feat for feat in layers[1].getFeatures() ]

selected_feats = []

for i, feat1 in enumerate(feats_lyr1):
    for j, feat2 in enumerate(feats_lyr2):
        if feat1.geometry().intersects(feat2.geometry()):
            area1 = feat1.geometry().intersection(feat2.geometry()).area()
            area2 = feat2.geometry().area()
            crit =area1/area2
            if crit > 0.8:
                selected_feats.append(feat2)

epsg = layers[0].crs().postgisSrid()

uri = "Polygon?crs=epsg:" + str(epsg) + "&index=yes"

mem_layer = QgsVectorLayer(uri,
                           "mem_layer",
                           "memory")

for i, feat in enumerate(selected_feats):
    feat.setAttributes(selected_feats[i].attributes())

prov = mem_layer.dataProvider()
attr = layers[1].dataProvider().fields().toList()
prov.addAttributes(attr)
mem_layer.updateFields()
prov.addFeatures(selected_feats)

QgsMapLayerRegistry.instance().addMapLayer(mem_layer)

Answer 1

Just add the source layer fields to a list, use addAttributes(), and updateFields() methods to add the fields:

prov = mem_layer.dataProvider()
attr = layers[0].dataProvider().fields().toList()
prov.addAttributes(attr)
mem_layer.updateFields()
prov.addFeatures(selected_feats)