pandas
JSON

Lees JSON

kan een string van de json of een bestandspad doorgeven aan een bestand met geldige json

In [99]: pd.read_json('[{"A": 1, "B": 2}, {"A": 3, "B": 4}]')
Out[99]:
   A  B
0  1  2
1  3  4

Als alternatief om geheugen te besparen:

with open('test.json') as f:
    data = pd.DataFrame(json.loads(line) for line in f)

Dataframe in geneste JSON zoals in flare.js-bestanden die worden gebruikt in D3.js

def to_flare_json(df, filename):
    """Convert dataframe into nested JSON as in flare files used for D3.js"""
    flare = dict()
    d = {"name":"flare", "children": []}
    
    for index, row in df.iterrows():
        parent = row[0]
        child = row[1]
        child_size = row[2]

        # Make a list of keys
        key_list = []
        for item in d['children']:
            key_list.append(item['name'])

        #if 'parent' is NOT a key in flare.JSON, append it
        if not parent in key_list:
            d['children'].append({"name": parent, "children":[{"value": child_size, "name": child}]})
        # if parent IS a key in flare.json, add a new child to it
        else:
            d['children'][key_list.index(parent)]['children'].append({"value": child_size, "name": child})
    flare = d
    # export the final result to a json file
    with open(filename +'.json', 'w') as outfile:
        json.dump(flare, outfile, indent=4)
    return ("Done")

Lees JSON uit bestand

Inhoud van file.json (één JSON-object per regel):

{"A": 1, "B": 2}
{"A": 3, "B": 4}

Hoe direct uit een lokaal bestand te lezen:

pd.read_json('file.json', lines=True)
# Output:
#    A  B
# 0  1  2
# 1  3  4