json extradata

dump:​写入json文件，一个文件只能写入一次， 多次dump会报错extra data。

f = open('BaiduStockInfo.json', 'w')

In [38]: json.dump(dict1, f)

In [39]: json.dump(dict2, f)

In [40]: f.close()

In [41]: f = open('BaiduStockInfo.json', 'r')

In [42]: json.load(f)

Traceback (most recent call last):

File "<ipython-input-42-676818aecd44>", line 1, in <module>

json.load(f)

File "D:\anaconda\lib\json\__init__.py", line 299, in load

parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)

File "D:\anaconda\lib\json\__init__.py", line 354, in loads

return _default_decoder.decode(s)

File "D:\anaconda\lib\json\decoder.py", line 342, in decode

raise JSONDecodeError("Extra data", s, end)

JSONDecodeError: Extra data

dumps:​需要写入多个obj,先dumps成json字符串，用‘+‘连接,一次dump。

 f = open('BaiduStockInfo.json', 'w')

    ...:

    ...: str1 = json.dumps(dict1) + json.dumps(dict2)

    ...:

    ...: json.dump(str1, f)

    ...:

    ...: f.close()

    ...:

    ...: f = open('BaiduStockInfo.json', 'r')

    ...:

    ...: json.load(f)

    ...:

Out[50]: '{"oi": 456}{"ko": 123}'