Standard way to express a date in a real number?

[sdhyok]

I am looking for a way to express a date in a real number
in Python.

For instance, in MatLab,
n = datenum(2001,12,19,18,0,0) returns n = 731204.75.

This kind of expression turned out to be very helpful
when handling or storing dates.

Is there any funtion for the purpose in Python (e.g. in datetime module)?

Daehyok Shin