get decimal part of a float number in python

Question

I would like my Python2 daemon to wake up and do something exactly on the second.

Is there a better way to get the decmal part of a floating point number for a sleep time other then:

now = time.time()               #get the current time in a floating point format
left_part = long(now)           #isolate out the integer part
right_part = now - left_part    #now get the decimal part
time.sleep(1 - right_part)      #and sleep for the remaining portion of this second.

The sleep time will be variable depending on how much work was done in this second.

Is there a "Sleep till" function I don't know about? or, is there a better way to handle this?

I would like my daemon to be as efficient as possible so as not to monopolize too much CPU from other processes.

Thanks. Mark.

Answer 1

time.sleep isn't guaranteed to wake up exactly when you tell it to, it can be somewhat inaccurate.

For getting the part after the decimal place, use the modulus (%) operator:

>>> 3.5 % 1
.5

e.g.:

>>> t = time.time()
>>> t
1430963764.102048
>>> 1 - t % 1
0.8979520797729492

As for "sleep til", you might be interested in the sched module, which is built around that idea: https://docs.python.org/2/library/sched