In [1]: import datetime
In [2]: d=datetime.datetime.now() #是一个对象
In [3]: d
Out[3]: datetime.datetime(2018, 8, 8, 18, 37, 48, 242295)
In [4]: print d
2018-08-08 18:37:48.242295
In [7]: type(d)
Out[7]: datetime.datetime
In [12]: d=datetime.datetime.now().strftime("%Y-%m-%d") #变成字符串
In [13]: d
Out[13]: '2018-08-08'
In [14]: print d
2018-08-08
In [15]: type(d)
Out[15]: str
In [16]: import json
In [17]: json.dumps(d) #可以使用json序列化
Out[17]: '"2018-08-08"'
In [18]: json.dumps(datetime.datetime.now()) #不可以使用json序列化
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-18-5898596fa331> in <module>()
----> 1 json.dumps(datetime.datetime.now()
TypeError: tzinfo argument must be None or of a tzinfo subclass, not type 'str'
In [20]: json.dumps(datetime.datetime.now().strftime("%Y-%m-%d"))
Out[20]: '"2018-08-08"'