Last record in the program in PyQGIS is not executed properly

Question

layer = vlayer4

provider = layer.dataProvider()

areas = [ feat.geometry().area() 
          for feat in layer.getFeatures() ]

field = QgsField("area", QVariant.Double)
provider.addAttributes([field])
layer.updateFields()

idx = layer.fieldNameIndex('area')

for area in areas:
    new_values = {idx : float(area)}
    provider.changeAttributeValues({areas.index(area):new_values})

This program runs properly and gives the desired results. However, it fails to execute to calculate the area of the last feature in the polygon shapefile. I have a polygon shapefile with 516 features. It rightly calculates the area of 515 features but terminates there and don't give the area of 516th feature.

Kadir Şahbaz · Answer

Iterate over features instead of areas to add area value to a new field. As @BERA states in his comment, it must be two features which have the same area.
Use like this:
provider = layer.dataProvider()

field = QgsField("area", QVariant.Double)
provider.addAttributes([field])
layer.updateFields()

idx = provider.fieldNameIndex('area')

# iteration over features
for feat in layer.getFeatures():
    provider.changeAttributeValues({feat.id(): {idx: feat.geometry().area()} })

Last record in the program in PyQGIS is not executed properly

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