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CHAPTER 10 ■ BATTERIES INCLUDED 227
Table 10-6. Some Important Functions in the time Module
Function
asctime([tuple])
localtime([secs])
mktime(tuple)
sleep(secs)
strptime(string[, format])
time()
Description
Converts time tuple to a string
Converts seconds to a date tuple, local time
Converts time tuple to local time
Sleeps (does nothing) for secs seconds
Parses a string into a time tuple
Current time (seconds since the epoch, UTC)
The function time.asctime formats the current time as a string, such as
>>> time.asctime()
'Fri Dec 21 05:41:27 2001'
You can also supply a date tuple (such as those created by localtime) if you don’t want the
current time. (For more elaborate formatting, see the strftime function, described in the standard
documentation.)
The function time.localtime converts a real number (seconds since epoch) to a date tuple,
local time. If you want universal time, use gmtime instead.
The function time.mktime converts a date tuple to the time since epoch in seconds; it is the
inverse of localtime.
The function time.sleep makes the interpreter wait for a given number of seconds.
The function time.strptime converts a string of the format returned by asctime to a date
tuple. (The optional format argument follows the same rules as those for strftime. See the
standard documentation.)
The function time.time returns the current (universal) time as seconds since the epoch.
Even though the epoch may vary from platform to platform, you can reliably time something
by storing the result of time before and after the event (such as a function call) and then computing
the difference. For an example of these functions, see the next section, which covers the random
module.
OTHER TIME FUNCTIONS
The functions shown in Table 10-6 are just a selection of those available from the time module. Most of the
functions in that module perform tasks similar to or related to those described in this section. If you need
something not covered by the functions described here, you should take a look at the section about the time
module in the standard library reference (http://python.org/doc/lib/module-time.html); chances
are you may find exactly what you are looking for.
There are also some more recent time-related modules available: datetime and timeit. You can find
more information about both in the library reference, and timeit is also discussed briefly in Chapter 16.