Iterate and extract several lists from a dictionary in Python-CodePudding

I have a dictionary like this:

dic = {'features': [{'type': 'Feature',
   'geometry': {'geodesic': False,
    'type': 'Point',
    'coordinates': [33.44904857310912, 52.340950190985474]},
   'id': '0',
   'properties': {'a1': 1.313, 
      'a2': -0.028, 'a3': 0.0026, 'a4': -0.025... 
      'a40': -0.056 ... 
   {'type': 'Feature',
   'geometry': {'geodesic': False,
    'type': 'Point',
    'coordinates': [33.817042613128294, 52.340950190985474]},
   'id': '1',
   'properties': {'a1': 1.319,
       'a2': -0.026, 'a3': 0.003,'a4': -0.045, ... 
       'a40': -0.032 ...... 

Almost 1000 ids, e.g. 'id': '0', 'id': '1'...'id': '960'

I want to iterate through the dictionary to extract a list of element containing 'a1', 'a2'... 'a40', separately. Something like this:

list_a1 = [1.313, 1.319... ]
list_a2 = [-0.028, -0.026 ...]

How to get these lists using Python?

CodePudding user response：

You can use something like this. Using setdefault makes it dynamic and any number of keys in properties will be included in the result.

dic = {'features': [{'type': 'Feature',
   'geometry': {'geodesic': False,
    'type': 'Point',
    'coordinates': [33.44904857310912, 52.340950190985474]},
   'id': '0',
   'properties': {'a1': 1.313,
    'a2': -0.028,
    'a3': 0.0026,
    'a4': -0.025,
    'a40': -0.056}},
  {'type': 'Feature',
   'geometry': {'geodesic': False,
    'type': 'Point',
    'coordinates': [33.817042613128294, 52.340950190985474]},
   'id': '1',
   'properties': {'a1': 1.319,
    'a2': -0.026,
    'a3': 0.003,
    'a4': -0.045,
    'a40': -0.032}}]}

separated_properties = {}
for feature in dic['features']:
    for key, val in feature['properties'].items():
        separated_properties.setdefault(key, []).append(val)

print(separated_properties)
print('a1: ', separated_properties['a1'])

Output

{'a1': [1.313, 1.319],
 'a2': [-0.028, -0.026],
 'a3': [0.0026, 0.003],
 'a4': [-0.025, -0.045],
 'a40': [-0.056, -0.032]}
a1:  [1.313, 1.319]