Python datetime时间戳问题

Question

I was trying to create a dictionary with time stamp as the key. the code is :

    >>> stamp = datetime.datetime(2012, 4, 12, 12, 26, int('13'))
    >>> new_dict = {}
    >>> new_dict[stamp] = 'one'
    >>> print new_dict
    {datetime.datetime(2012, 4, 12, 12, 26, 13): 'one'}
    >>> print stamp
    2012-04-12 12:26:13

Why does it not take the key as '2012-04-12 12:26:13' and instead taking the expression 'datetime.datetime()' as the key?

Answer 1

Because stamp is a datetime.datetime object. When you print it, a string representing this object is printed. If you want a str key, try

new_dict[str(stamp)] = 'one'

Answer 2

'2012-04-12 12:26:13' is a string, and stamp in your example is a datetime.datetime object.

You can use datetime objects directly as keys in a dictionnary, as stated in the documentation (two identical datetimes will have the same hash).