I'm trying to get todays and yesterdays time using Python's time
module.
This for me works for todays date:
dt = time.strptime(time.strftime("%d/%m/%Y"),'%d/%m/%Y')
But I don't know how to get yesterdays date.
I've found many tutorials where the datetime
module is used but nothing where time
module is used.
How can I do that? And is there a better way to get todays date (struct_time
)?
To get yesterday's struct_time
, use any of many existing datetime
solutions and call .timetuple()
to get struct_time
e.g.:
#!/usr/bin/env python
from datetime import date, timedelta
today = date.today()
yesterday = today - timedelta(1)
print(yesterday.timetuple())
# -> time.struct_time(tm_year=2015, tm_mon=4, tm_mday=22, tm_hour=0, tm_min=0, tm_sec=0, tm_wday=2, tm_yday=112, tm_isdst=-1)
It produces the correct day in the local timezone even around DST transitions.
See How can I subtract a day from a python date? if you want to find the corresponding UTC time (get yesterday as an aware datetime
object).
You could also get yesterday using only time
module (but less directly):
#!/usr/bin/env python
import time
def posix_time(utc_time_tuple):
"""seconds since Epoch as defined by POSIX."""
# from https://gist.github.com/zed/ff4e35df3887c1f82002
tm_year = utc_time_tuple.tm_year - 1900
tm_yday = utc_time_tuple.tm_yday - 1
tm_hour = utc_time_tuple.tm_hour
tm_min = utc_time_tuple.tm_min
tm_sec = utc_time_tuple.tm_sec
# http://pubs.opengroup.org/stage7tc1/basedefs/V1_chap04.html#tag_04_15
return (tm_sec + tm_min*60 + tm_hour*3600 + tm_yday*86400 +
(tm_year-70)*31536000 + ((tm_year-69)//4)*86400 -
((tm_year-1)//100)*86400 + ((tm_year+299)//400)*86400)
now = time.localtime()
yesterday = time.gmtime(posix_time(now) - 86400)
print(yesterday)
# -> time.struct_time(tm_year=2015, tm_mon=4, tm_mday=22, tm_hour=22, tm_min=6, tm_sec=16, tm_wday=2, tm_yday=112, tm_isdst=0)
It assumes that time.gmtime()
accepts POSIX timestamp on the given platform (Python's stdlib breaks otherwise e.g., if non-POSIX TZ=right/UTC
is used). calendar.timegm()
could be used instead of posix_time()
but the former may use datetime
internally.
Note: yesterday
represents local time in both solutions (gmtime()
is just a simple way to implement subtraction here). Both solutions use naive timezone-unaware time objects and therefore the result may be ambiguous or even non-existent time though unless the local timezone has skipped yesterday (e.g., Russia had skipped several days in February 1918) then the date is correct anyway.
To start with, there is a more straight-forward way to get the current date:
dt = time.localtime()
To get the previous day's date, you need to subtract 24 hours from the current time. This might have some glitches around DST transitions but I'll leave those as an exercise for the reader.
dt = time.localtime(time.time() - 86400)
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