使用字典理解过滤python字典

Question

I have a dictionary that is really a geojson:

points = {
    'crs': {'properties': {'name': 'urn:ogc:def:crs:OGC:1.3:CRS84'}, 'type': 'name'},
    'features': [
        {'geometry': {
            'coordinates':[[[-3.693162104185235, 40.40734504903418],
                            [-3.69320229317164, 40.40719570724241],
                            [-3.693227952841606, 40.40698546120488],
                            [-3.693677594635894, 40.40712700492216]]],
            'type': 'Polygon'},
         'properties': {
             'name': 'place1',
             'temp': 28},
         'type': 'Feature'
        },
        {'geometry': {
            'coordinates': [[[-3.703886381691941, 40.405197271972035],
                             [-3.702972834622821, 40.40506272989243],
                             [-3.702552994966045, 40.40506798079752],
                             [-3.700985024825222, 40.405500820623814]]],
            'type': 'Polygon'},
         'properties': {
             'name': 'place2',
             'temp': 27},
         'type': 'Feature'
        },
        {'geometry': {
            'coordinates': [[[-3.703886381691941, 40.405197271972035],
                             [-3.702972834622821, 40.40506272989243],
                             [-3.702552994966045, 40.40506798079752],
                             [-3.700985024825222, 40.405500820623814]]],
            'type': 'Polygon'},
         'properties': {
             'name': 'place',
             'temp': 25},
         'type': 'Feature'
        }
    ],
    'type': u'FeatureCollection'
}

I would like to filter it to stay only with places that have a specific temperature, for example, more than 25 degrees Celsius.

I have managed to do it this way:

dict(crs = points["crs"],
     features = [i for i in points["features"] if i["properties"]["temp"] > 25],
     type = points["type"])

But I wondered if there was any way to do it more directly, with dictionary comprehension.

Thank you very much.

Answer 1

I'm very late. A dict compreheneison won't help you since you have only three keys. But if you meet the following conditions: 1. you don't need a copy of features (eg your dict is read only); 2. you don't need index access to features , you my use a generator comprehension instead of a list comprehension:

dict(crs = points["crs"],
                features = (i for i in points["features"] if i["properties"]["temp"] > 25),
                type = points["type"])

The generator is created in constant time, while the list comprehension is created in O(n). Furthermore, if you create a lot of those dicts, you have only one copy of the features in memory.