Python JSON 序列化 Mongodb
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JSON serializing Mongodb
提问by RockScience
I am using the python package pymongo to retrieve data from a mongodb database.
我正在使用 python 包 pymongo 从 mongodb 数据库中检索数据。
>>> r = collection.find() # returns an object of class 'Cursor'
Then I convert to a list
然后我转换为列表
>>> l = list(r) # returns a 'list' of 'dict'
here is what print(l) returns:
这是 print(l) 返回的内容：
>>> [{u'date': datetime.datetime(2009, 11, 10, 10, 45), u'_id': 1, u'name': u'name1', u'value': 11},{u'date': datetime.datetime(2013, 11, 10, 10, 45), u'_id': 2, u'name': u'name2', u'value': 22}]
Now I need to convert to JSON so that I can manipulate it.
现在我需要转换为 JSON 以便我可以操作它。
>>> json.dumps(l)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/json/__init__.py", line 231, in dumps
return _default_encoder.encode(obj)
File "/usr/lib/python2.7/json/encoder.py", line 201, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/usr/lib/python2.7/json/encoder.py", line 264, in iterencode
return _iterencode(o, 0)
File "/usr/lib/python2.7/json/encoder.py", line 178, in default
raise TypeError(repr(o) + " is not JSON serializable")
TypeError: datetime.datetime(2009, 11, 12, 11, 14) is not JSON serializable
I have also tried to follow http://api.mongodb.org/python/1.7/api/pymongo/json_util.htmlwithout success: Edit: the recent version of the link is http://api.mongodb.org/python/current/api/bson/json_util.html
我也曾尝试遵循http://api.mongodb.org/python/1.7/api/pymongo/json_util.html没有成功： 编辑：链接的最新版本是http://api.mongodb.org/python /current/api/bson/json_util.html
>>> json.dumps(l, default=json_util.default)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'json_util' is not defined
Note:precisely I need to push this result to R using the R package rPython and its function rPython::python.get("l")
注意：确切地说，我需要使用 R 包 rPython 及其函数 rPython::python.get("l") 将此结果推送到 R
Side Question: What is the u (u'Date', u'name', etc..) before each field in the list of dict?
附带问题：dict 列表中每个字段之前的 u（u'Date'、u'name' 等）是什么？
采纳答案by Rafa
The pymongo documentation you pointed is obsolete. If you're using version 1.7 I recommend updating. With a more recent version you can do this:
您指出的 pymongo 文档已过时。如果您使用的是 1.7 版，我建议您更新。使用更新的版本，您可以执行以下操作：
from bson.json_util import dumps
dumps(l)
http://api.mongodb.org/python/current/api/bson/json_util.html
http://api.mongodb.org/python/current/api/bson/json_util.html
Side answer: u'name', u'date', u'_id'etc are the names of the fields of the document on the database.
旁答：u'name', u'date', u'_id'etc 是数据库上文档的字段名称。
回答by DhruvPathak
from bson import json_util
json.dumps(result,default=json_util.default)
回答by rbansal
I was facing the same issue, I wrote a code that converts document to dictionary. You can use that for reference. Pass the object obtained by find_one() into documentToJson() method and the results of find() into convertDocumentsToJson. There is type in the name Json, instead the code converts to Dict rather than json.
我遇到了同样的问题，我编写了一个将文档转换为字典的代码。您可以将其用作参考。将 find_one() 获得的对象传递给 documentToJson() 方法，将 find() 的结果传递给 convertDocumentsToJson。名称 Json 中有类型，而是代码转换为 Dict 而不是 json。
from bson.json_util import dumps
class UtilService:
def __init__(self):
pass
@staticmethod
def pinCodeParser(path):
location = {}
f = open(path)
for line in f:
words = line.split()
location[words[1]] = (words[-3],words[-2])
return location
@staticmethod
def listHelper(str):
s = []
str = str.split(',')
for e in str:
s.append(e.replace("[","").replace("]",""))
return s
@staticmethod
def parseList(str):
if ',' in str:
return UtilService.listHelper(str)
return str
@staticmethod
def trimStr(str):
return str.replace('"','')
@staticmethod
def documentToJson(document):
document = eval(dumps(document))
mp = {}
for key, value in document.iteritems():
if "_id" in key:
mp["id"] = str(value["$oid"])
else:
mp[ UtilService.trimStr(key) ] = UtilService.parseList( value )
return mp
@staticmethod
def convertDocumentsToJson(documents):
result = []
for document in documents:
result.append(UtilService.documentToJson(document))
return result
回答by Jonathan Aspeling
This thread helped me - thank you.
这个线程帮助了我 - 谢谢。
Wanted to share my final solution to get the JSON back into a JSON/Dictionary Object: (Based on your example)
想分享我的最终解决方案，将 JSON 恢复为 JSON/Dictionary 对象：（基于您的示例）
from bson.json_util import dumps, loads
r = collection.find()
l = list(r) # Converts object to list
d = dumps(l) # Converts to String
dict_needed = loads(d[0]) # Serializes String and creates dictionary
Now you have the JSON in a dictionary object and can edit as needed.
现在您在字典对象中拥有了 JSON，并且可以根据需要进行编辑。
