Python Time Conversion

From http://emilics.com/blog/article/python_time.html

Python Time Conversion

In python, there are four types that are commonly used to manage time. Timestamps, time tuples, datetime objects, and strings. Programmers often have to convert between these types depending on the situation or API. This article will describe all conversion patterns.

Python Time Conversion Table

Table 1 shows the python conversion table. Click on the pattern you want to see.

Table 1. python time conversion table

input \ output	datetime	time tuple	time stamp	string
datetime	—	datetime ↓ time tuple	datetime ↓ time stamp	datetime ↓ string
time tuple	time tuple ↓ datetime	—	time tuple ↓ time stamp	time tuple ↓ string
time stamp	time stamp ↓ datetime	time stamp ↓ time tuple	—	time stamp ↓ string
string	string ↓ datetime	string ↓ time tuple	string ↓ time stamp	—

datetime → time tuple

>>> dt = datetime.datetime(2010, 12, 31, 23, 59, 59)
>>> tt = dt.timetuple()
>>> print tt
time.struct_time(tm_year=2010, tm_mon=12, tm_mday=31, tm_hour=23, tm_min=59, tm_sec=59, ...)

datetime → time tuple

datetime → time stamp

>>> dt = datetime.datetime(2010, 12, 31, 23, 59, 59)
>>> ts = time.mktime(dt.timetuple())
>>> print ts
1293868799.0

datetime → time stamp

datetime → string

>>> dt = datetime.datetime(2010, 12, 31, 23, 59, 59)
>>> st = dt.strftime('%Y-%m-%d %H:%M:%S')
>>> print st
2010-12-31 23:59:59

datetime → string

time tuple → datetime

>>> tt = (2010, 12, 31, 23, 59, 59, 4, 365, 0)
>>> dt = datetime.datetime(tt[0], tt[1], tt[2], tt[3], tt[4], tt[5])
>>> print dt
2010-12-31 23:59:59
>>>
>>> dt = datetime.datetime(*tt[0:6])  # same with the code above
>>> print dt
2010-12-31 23:59:59

time tuple → datetime

time tuple → time stamp

>>> tt = (2010, 12, 31, 23, 59, 59, 4, 365, 0)
>>> ts = time.mktime(tt)
>>> print ts
1293868799.0

time tuple → time stamp

time tuple → string

>>> tt = (2010, 12, 31, 23, 59, 59, 4, 365, 0)
>>> st = time.strftime('%Y-%m-%d %H:%M:%S', tt)
>>> print st
2010-12-31 23:59:59

time tuple → string

time stamp → datetime

>>> ts = 1293868799.0
>>> dt = datetime.datetime.fromtimestamp(ts)     # for local time
>>> print dt
2010-12-31 23:59:59
>>>
>>> dt = datetime.datetime.utcfromtimestamp(ts)  # for UTC
>>> print dt
2011-01-01 07:59:59

time stamp → datetime

time stamp → time tuple

>>> ts = 1293868799.0
>>> tt = time.localtime(ts)
>>> print tt
time.struct_time(tm_year=2010, tm_mon=12, tm_mday=31, tm_hour=23, tm_min=59, tm_sec=59, ...)
>>>
>>> tt = time.gmtime(ts)
>>> print tt
time.struct_time(tm_year=2011, tm_mon=1, tm_mday=1, tm_hour=7, tm_min=59, tm_sec=59, ...)

time stamp → time tuple

time stamp → string

>>> ts = 1293868799.0
>>> st = datetime.datetime.fromtimestamp(ts).strftime('%Y-%m-%d %H:%M:%S')
>>> print st
2010-12-31 23:59:59
>>>
>>> st = datetime.datetime.utcfromtimestamp(ts).strftime('%Y-%m-%d %H:%M:%S')
>>> print st
2011-01-01 07:59:59

time stamp → string

string → datetime

>>> s = '2010-12-31 23:59:59'
>>> dt = datetime.datetime.strptime(s, '%Y-%m-%d %H:%M:%S')
>>> print dt
2010-12-31 23:59:59

string → datetime

string → time tuple

>>> st = '2010-12-31 23:59:59'
>>> tt = time.strptime(st, '%Y-%m-%d %H:%M:%S')
>>> print tt
time.struct_time(tm_year=2010, tm_mon=12, tm_mday=31, tm_hour=23, tm_min=59, tm_sec=59, ...)

string → time tuple

string → time stamp

>>> s = '2010-12-31 23:59:59'
>>> ts = time.mktime(time.strptime(s, '%Y-%m-%d %H:%M:%S'))
>>> print ts
1293868799.0

string → time stamp