基于其他矢量图层属性（pyqgis）创建新字段

Question

我想根据向量层“Buildings”和“Intersection”中的属性在vector layer“Join”中创建一个新字段，但是PyQgis返回了一系列工作编号，特别是字段“Intersection”的第一个特征值（我想错误在for循环的脚本/序列中）。你能帮帮我吗？在

featuresB=layerBuildings.getFeatures() 
featuresJ=layerJoin.getFeatures() 
featuresI=layerIntersection.getFeatures()    
for fJ in featuresJ:
    for fI in featuresI:
         for fB in featuresB:
             if fI.geometry().area()*2>=fB.geometry().area():
                print fI[field_x]
             else:
                print fJ[field_y]

Answer 1

第二，你要求完整的代码：这里有一些小的改动：

joined_layer=QgsVectorLayer(path,name,"ogr") 
intersected_layer=QgsVectorLayer(path,name,"ogr") 

featuresJ=joined_layer.getFeatures() 
featuresI=intersected_layer.getFeatures() 
featuresB=Bld_layer.getFeatures() 

for fJ in featuresJ: 
   for fI in featuresI: 
     geomI=fI.geometry() #lo piglia 
     for fB in featuresB: geomB=fB.geometry() 
       if geomI.area()*2>=geomB.area():
          val= fI[1] 
       else: 
          val= fJ[2] 
       print val