PyQGIS getting a dictionary for each feature of a layer with their attribute values

QgsJsonUtils class has exportAttributes method for getting attributes as dict.

Solution 1:

Making a dictionary including feature id as key, attributes map as value:

{feature1.id: {attr1: value, attr2: value, ...},
 feature2.id: {attr1: value, attr2: value, ...},
 ...}

layer = QgsProject.instance().mapLayersByName('LAYER_NAME')[0]
features_dict = {f.id(): QgsJsonUtils.exportAttributes(f) for f in layer.getFeatures()}

Solution 2:

Making a list including attributes map (dict) of features:

[{attr1: value, attr2: value, ...}, # feature 1
 {attr1: value, attr2: value, ...}, # feature 2
 ...]

layer = QgsProject.instance().mapLayersByName('LAYER_NAME')[0]
features_list = [QgsJsonUtils.exportAttributes(f) for f in layer.getFeatures()]

The snippet below should help you. It just prints a dictionary for each feature to the console, but you could do something else with the feature attribute dictionaries if you wanted.

layer = iface.activeLayer()

def print_atts_dict(layer, feature):
    flds = [f for f in layer.fields()]
    atts = {}
    for f in flds:
        atts[f.name()] = feature[f.name()]
    print(atts)
    
for f in layer.getFeatures():
    print_atts_dict(layer, f)

# get the fields and features:
fields = indiv.fields()
features = indiv.getFeatures()

# initialise an empty dict with each field name:
attdict = {}
for field in fields:
    attdict[field.name()] = []

# for each field in each feature, append the relevant field data to the dict item:
for feature in features:
  for field in fields:
    v = feature[field.name()]
    attdict[field.name()].append(v)

print(attdict)

That gives a dict that looks like this for some Ghana regions:

{'shapeName': ['Greater Accra', 'Central', 'Western', 'Eastern', 'Ashanti', 'Volta', 'Brong Ahafo', 'Northern', 'Upper West', 'Upper East'],
 'shapeISO': ['GH-AA', 'GH-CP', 'GH-WP', 'GH-EP', 'GH-AH', 'GH-TV', 'GH-BA', 'GH-NP', 'GH-UW', 'GH-UE'],
 'shapeID': ['GHA-ADM1-1590546715-B1', 'GHA-ADM1-1590546715-B2', 'GHA-ADM1-1590546715-B3', 'GHA-ADM1-1590546715-B4', 'GHA-ADM1-1590546715-B5', 'GHA-ADM1-1590546715-B6', 'GHA-ADM1-1590546715-B7', 'GHA-ADM1-1590546715-B8', 'GHA-ADM1-1590546715-B9', 'GHA-ADM1-1590546715-B10'],
 'shapeGroup': ['GHA', 'GHA', 'GHA', 'GHA', 'GHA', 'GHA', 'GHA', 'GHA', 'GHA', 'GHA'], 'shapeType': ['ADM1', 'ADM1', 'ADM1', 'ADM1', 'ADM1', 'ADM1', 'ADM1', 'ADM1', 'ADM1', 'ADM1']}

Which I think is what you are after.