How to count points with certain attribute within the current Print composer atlas feature in QGIS 2.8?

Question

I need to achieve exactly what the below script written by Jacob (found here) does, with the addition that I only want to count the points if column B in the point layers attribute field is greater then zero.

Since I'm a rookie with Python I can't figure out how to re-write the code to do that!?

from qgis.core import *
from qgis.gui import *
from qgis.utils import iface

@qgsfunction(args="auto", group='Custom')
def countPointsInCurrentAltlasFeature(pointLayerName, geomAtlas, feature, parent):
    # If point geom is empty, return 0
    if (geomAtlas is None):
        return 0

    # Get point layer reference from layername
    pointLayer = QgsMapLayerRegistry.instance().mapLayersByName(pointLayerName)[0]

    # Raise if layer not found
    if pointLayer is None:
        raise Exception("Layer not found: " + pointLayerName)

    # Count point within current Atlas feature
    countPoint = 0
    for pointFeature in pointLayer.getFeatures():
        pointGeom = pointFeature.geometry()
        if (pointGeom is None):
            continue
        if pointGeom.within(geomAtlas):
            countPoint += 1

    return countPoint

I've tried to change the last countPoint += 1 to IF column "B" > 0 THEN countPoint += 1 but the script wont run and the error doesn't provide any guidance.

Answer 1

To get the field attribute use something like pointFeature['fieldname'], try this:

for pointFeature in pointLayer.getFeatures():
    pointGeom = pointFeature.geometry()
    if (pointGeom is None):
        continue
    if pointGeom.within(geomAtlas):
        if pointFeature['B'] > 0: # include field name within quotes
            countPoint += 1