使用Python将元素附加到JSON dict（geojson）

Question

I would like to add style to my geojson through Python. The current features currently do not have any style elements. I want to append style and then fill. However, when I do, nothing is added to the file. It is the same as before

import json

with open('test.json') as f:
    data = json.load(f)

for feature in data['features']:
    feature.append("style")
    feature["style"].append({"fill":color})

Sample GeoJson

{
"type": "FeatureCollection",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },

"features": [
{ "type": "Feature", "properties": { "STATEFP": "17", "COUNTYFP": "019", "TRACTCE": "005401", "BLKGRPCE": "2", "GEOID": "170190054012", "NAMELSAD": "Block Group 2", "MTFCC": "G5030", "FUNCSTAT": "S", "ALAND": 574246.000000, "AWATER": 4116.000000, "INTPTLAT": "+40.1238204", "INTPTLON": "-088.2038105", "GISJOIN": "G17001900054012", "STUSPS": "IL", "SHAPE_AREA": 578361.706954, "SHAPE_LEN": 3489.996273, "census_block_income_YEAR": "2009-2013", "census_block_income_STATE": "Illinois", "census_block_income_STATEA": 17, "census_block_income_COUNTY": "Champaign County"}}]}

I'm trying to get the end results to be:

    {
"type": "FeatureCollection",
"crs": { "type": "name", "properties": { "name": "urn:ogc:def:crs:OGC:1.3:CRS84" } },

"features": [
{ "type": "Feature", "properties": { "STATEFP": "17", "COUNTYFP": "019", "TRACTCE": "005401", "BLKGRPCE": "2", "GEOID": "170190054012", "NAMELSAD": "Block Group 2", "MTFCC": "G5030", "FUNCSTAT": "S", "ALAND": 574246.000000, "AWATER": 4116.000000, "INTPTLAT": "+40.1238204", "INTPTLON": "-088.2038105", "GISJOIN": "G17001900054012", "STUSPS": "IL", "SHAPE_AREA": 578361.706954, "SHAPE_LEN": 3489.996273, "census_block_income_YEAR": "2009-2013", "census_block_income_STATE": "Illinois", "census_block_income_STATEA": 17, "census_block_income_COUNTY": "Champaign County"},"style"{fill:"red"}}]}

Answer 1

You are working with list of dictionaries here, dictionary hasn't method append , you can create new key like here:

for feature in data['features']:
    feature["style"] = {"fill":color}

Seems that you need rewrite file with JSON:

with open('test.json', 'w') as f:
    json.dump(data, f)

Answer 2

When you type

for feature in data['features']:

every feature will be an item of the list that is data['features'] . Each item there is a dictionary, so you are calling the wrong method ( append is a method of lists).

You could write

for feature in data['features']:
    feature.update({"style": {"fill": "red"}})

Finally, if you want the file from which you got the initial json structure to be altered, make sure to write the now updated data structure back to a file:

with open('output2.json', 'w') as f:
    json.dump(data, f)

Answer 3

There is no append method in a dictionary. One should use update .

import pprint as pp
for feature in data['features']:
    feature.update({'style':{'fill': 'red'}})

pp.pprint(data)

Output:

{'crs': {'properties': {'name': 'urn:ogc:def:crs:OGC:1.3:CRS84'},
         'type': 'name'},
 'features': [{'properties': {'ALAND': 574246.0,
                              'AWATER': 4116.0,
                              'BLKGRPCE': '2',
                              'COUNTYFP': '019',
                              'FUNCSTAT': 'S',
                              'GEOID': '170190054012',
                              'GISJOIN': 'G17001900054012',
                              'INTPTLAT': '+40.1238204',
                              'INTPTLON': '-088.2038105',
                              'MTFCC': 'G5030',
                              'NAMELSAD': 'Block Group 2',
                              'SHAPE_AREA': 578361.706954,
                              'SHAPE_LEN': 3489.996273,
                              'STATEFP': '17',
                              'STUSPS': 'IL',
                              'TRACTCE': '005401',
                              'census_block_income_COUNTY': 'Champaign County',
                              'census_block_income_STATE': 'Illinois',
                              'census_block_income_STATEA': 17,
                              'census_block_income_YEAR': '2009-2013'},
               'style': {'fill': 'red'},
               'type': 'Feature'}],
 'type': 'FeatureCollection'}

Answer 4

You never write your changes back to the file. Add the following to the end of your code:

with open('test.json','w') as f:
    json.dump(data, f)