我有一个基本的字典如下:
sample = {}
sample['title'] = "String"
sample['somedate'] = somedatetimehere
当我尝试做jsonify(sample)时，我得到:
TypeError: datetime.datetime(2012, 8, 8, 21, 46, 24, 862000) is not JSON serializable
我该怎么做才能使我的字典样本克服上面的错误呢?
注意:虽然它可能不相关，字典是从mongodb的记录检索中生成的，当我打印出str(sample['somedate'])时，输出是2012-08-08 21:46:24.862000。
当前回答
我可能不是百分百正确， 这是实现序列化的简单方法
#!/usr/bin/python
import datetime,json
sampledict = {}
sampledict['a'] = "some string"
sampledict['b'] = datetime.datetime.now()
print sampledict # output : {'a': 'some string', 'b': datetime.datetime(2017, 4, 15, 5, 15, 34, 652996)}
#print json.dumps(sampledict)
'''
output :
Traceback (most recent call last):
File "./jsonencodedecode.py", line 10, in <module>
print json.dumps(sampledict)
File "/usr/lib/python2.7/json/__init__.py", line 244, in dumps
return _default_encoder.encode(obj)
File "/usr/lib/python2.7/json/encoder.py", line 207, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/usr/lib/python2.7/json/encoder.py", line 270, in iterencode
return _iterencode(o, 0)
File "/usr/lib/python2.7/json/encoder.py", line 184, in default
raise TypeError(repr(o) + " is not JSON serializable")
TypeError: datetime.datetime(2017, 4, 15, 5, 16, 17, 435706) is not JSON serializable
'''
sampledict['b'] = datetime.datetime.now().strftime("%B %d, %Y %H:%M %p")
afterdump = json.dumps(sampledict)
print afterdump #output : {"a": "some string", "b": "April 15, 2017 05:18 AM"}
print type(afterdump) #<type 'str'>
afterloads = json.loads(afterdump)
print afterloads # output : {u'a': u'some string', u'b': u'April 15, 2017 05:18 AM'}
print type(afterloads) # output :<type 'dict'>
其他回答
以下是我的解决方案:
import json
class DatetimeEncoder(json.JSONEncoder):
def default(self, obj):
try:
return super().default(obj)
except TypeError:
return str(obj)
然后你可以这样使用它:
json.dumps(dictionnary, cls=DatetimeEncoder)
试着用一个例子来解析它:
#!/usr/bin/env python
import datetime
import json
import dateutil.parser # pip install python-dateutil
class JSONEncoder(json.JSONEncoder):
def default(self, obj):
if isinstance(obj, datetime.datetime):
return obj.isoformat()
return super(JSONEncoder, self).default(obj)
def test():
dts = [
datetime.datetime.now(),
datetime.datetime.now(datetime.timezone(-datetime.timedelta(hours=4))),
datetime.datetime.utcnow(),
datetime.datetime.now(datetime.timezone.utc),
]
for dt in dts:
dt_isoformat = json.loads(json.dumps(dt, cls=JSONEncoder))
dt_parsed = dateutil.parser.parse(dt_isoformat)
assert dt == dt_parsed
print(f'{dt}, {dt_isoformat}, {dt_parsed}')
# 2018-07-22 02:22:42.910637, 2018-07-22T02:22:42.910637, 2018-07-22 02:22:42.910637
# 2018-07-22 02:22:42.910643-04:00, 2018-07-22T02:22:42.910643-04:00, 2018-07-22 02:22:42.910643-04:00
# 2018-07-22 06:22:42.910645, 2018-07-22T06:22:42.910645, 2018-07-22 06:22:42.910645
# 2018-07-22 06:22:42.910646+00:00, 2018-07-22T06:22:42.910646+00:00, 2018-07-22 06:22:42.910646+00:00
if __name__ == '__main__':
test()
Another approach is to adopt a concept from FEEL (the Friendly Enough Expression Language) defined in DMN (Decision Model Notation) - namely @strings. Any string starting with @" and ending with " is decoded separately with FEEL decoding. Of course the sender and the receiver have to agree to this convention, but ... the code below lets you encode lots of other things as well as dates, times, date/times, timedeltas. You can encode year/month durations and ranges (so long as you except a 4 element tuple of chr, expr, expr, chr as being a good representation of a range - where the two chrs are open/close brackets). So, @"P4Y2M" is a duration of 4 years and 2 months. @"P2DT5H" is a timedelta of 2 days and 4 hours, @"(2021-01-02 .. 2021-12-31)" is a year range.
下面的代码可用于序列化和反序列化@strings。
import datetime
import pySFeel
parser = pySFeel.SFeelParser()
def convertAtString(thisString):
# Convert an @string
(status, newValue) = parser.sFeelParse(thisString[2:-1])
if 'errors' in status:
return thisString
else:
return newValue
def convertIn(newValue):
if isinstance(newValue, dict):
for key in newValue:
if isinstance(newValue[key], int):
newValue[key] = float(newValue[key])
elif isinstance(newValue[key], str) and (newValue[key][0:2] == '@"') and (newValue[key][-1] == '"'):
newValue[key] = convertAtString(newValue[key])
elif isinstance(newValue[key], dict) or isinstance(newValue[key], list):
newValue[key] = convertIn(newValue[key])
elif isinstance(newValue, list):
for i in range(len(newValue)):
if isinstance(newValue[i], int):
newValue[i] = float(newValue[i])
elif isinstance(newValue[i], str) and (newValue[i][0:2] == '@"') and (newValue[i][-1] == '"'):
newValue[i] = convertAtString(newValue[i])
elif isinstance(newValue[i], dict) or isinstance(newValue[i], list):
newValue[i] = convertIn(newValue[i])
elif isinstance(newValue, str) and (newValue[0:2] == '@"') and (newValue[-1] == '"'):
newValue = convertAtString(newValue)
return newValue
def convertOut(thisValue):
if isinstance(thisValue, datetime.date):
return '@"' + thisValue.isoformat() + '"'
elif isinstance(thisValue, datetime.datetime):
return '@"' + thisValue.isoformat(sep='T') + '"'
elif isinstance(thisValue, datetime.time):
return '@"' + thisValue.isoformat() + '"'
elif isinstance(thisValue, datetime.timedelta):
sign = ''
duration = thisValue.total_seconds()
if duration < 0:
duration = -duration
sign = '-'
secs = duration % 60
duration = int(duration / 60)
mins = duration % 60
duration = int(duration / 60)
hours = duration % 24
days = int(duration / 24)
return '@"%sP%dDT%dH%dM%fS"' % (sign, days, hours, mins, secs)
elif isinstance(thisValue, bool):
return thisValue:
elif thisValue is None:
return thisValue:
elif isinstance(thisValue, int):
sign = ''
if thisValue < 0:
thisValue = -thisValue
sign = '-'
years = int(thisValue / 12)
months = (thisValue % 12)
return '@"%sP%dY%dM"' % (sign, years, months)
elif isinstance(thisValue, tuple) and (len(thisValue) == 4):
(lowEnd, lowVal, highVal, highEnd) = thisValue
return '@"' + lowEnd + str(lowVal) + ' .. ' + str(highVal) + highEnd
elif thisValue is None:
return 'null'
elif isinstance(thisValue, dict):
for item in thisValue:
thisValue[item] = convertOut(thisValue[item])
return thisValue
elif isinstance(thisValue, list):
for i in range(len(thisValue)):
thisValue[i] = convertOut(thisValue[i])
return thisValue
else:
return thisValue
对于不需要或不想使用pymongo库的其他人。你可以用这个小片段轻松实现datetime JSON转换:
def default(obj):
"""Default JSON serializer."""
import calendar, datetime
if isinstance(obj, datetime.datetime):
if obj.utcoffset() is not None:
obj = obj - obj.utcoffset()
millis = int(
calendar.timegm(obj.timetuple()) * 1000 +
obj.microsecond / 1000
)
return millis
raise TypeError('Not sure how to serialize %s' % (obj,))
然后像这样使用它:
import datetime, json
print json.dumps(datetime.datetime.now(), default=default)
输出:
'1365091796124'
我可能不是百分百正确， 这是实现序列化的简单方法
#!/usr/bin/python
import datetime,json
sampledict = {}
sampledict['a'] = "some string"
sampledict['b'] = datetime.datetime.now()
print sampledict # output : {'a': 'some string', 'b': datetime.datetime(2017, 4, 15, 5, 15, 34, 652996)}
#print json.dumps(sampledict)
'''
output :
Traceback (most recent call last):
File "./jsonencodedecode.py", line 10, in <module>
print json.dumps(sampledict)
File "/usr/lib/python2.7/json/__init__.py", line 244, in dumps
return _default_encoder.encode(obj)
File "/usr/lib/python2.7/json/encoder.py", line 207, in encode
chunks = self.iterencode(o, _one_shot=True)
File "/usr/lib/python2.7/json/encoder.py", line 270, in iterencode
return _iterencode(o, 0)
File "/usr/lib/python2.7/json/encoder.py", line 184, in default
raise TypeError(repr(o) + " is not JSON serializable")
TypeError: datetime.datetime(2017, 4, 15, 5, 16, 17, 435706) is not JSON serializable
'''
sampledict['b'] = datetime.datetime.now().strftime("%B %d, %Y %H:%M %p")
afterdump = json.dumps(sampledict)
print afterdump #output : {"a": "some string", "b": "April 15, 2017 05:18 AM"}
print type(afterdump) #<type 'str'>
afterloads = json.loads(afterdump)
print afterloads # output : {u'a': u'some string', u'b': u'April 15, 2017 05:18 AM'}
print type(afterloads) # output :<type 'dict'>
