6.9 time -- Time access and conversions

This module provides various time-related functions. It is always available, but not all functions are available on all platforms.

An explanation of some terminology and conventions is in order.

The module defines the following functions and data items:

accept2dyear
Boolean value indicating whether two-digit year values will be accepted. This is true by default, but will be set to false if the environment variable $PYTHONY2K has been set to a non-empty string. It may also be modified at run time.

altzone
The offset of the local DST timezone, in seconds west of UTC, if one is defined. This is negative if the local DST timezone is east of UTC (as in Western Europe, including the UK). Only use this if daylight is nonzero.

asctime (tuple)
Convert a tuple representing a time as returned by gmtime() or localtime() to a 24-character string of the following form: 'Sun Jun 20 23:21:05 1993'. Note: unlike the C function of the same name, there is no trailing newline.

clock ()
Return the current CPU time as a floating point number expressed in seconds. The precision, and in fact the very definition of the meaning of ``CPU time'', depends on that of the C function of the same name, but in any case, this is the function to use for benchmarking Python or timing algorithms.

ctime (secs)
Convert a time expressed in seconds since the epoch to a string representing local time. ctime(secs) is equivalent to asctime(localtime(secs)).

daylight
Nonzero if a DST timezone is defined.

gmtime (secs)
Convert a time expressed in seconds since the epoch to a time tuple in UTC in which the dst flag is always zero. Fractions of a second are ignored. See above for a description of the tuple lay-out.

localtime (secs)
Like gmtime() but converts to local time. The dst flag is set to 1 when DST applies to the given time.

mktime (tuple)
This is the inverse function of localtime(). Its argument is the full 9-tuple (since the dst flag is needed; use -1 as the dst flag if it is unknown) which expresses the time in local time, not UTC. It returns a floating point number, for compatibility with time(). If the input value cannot be represented as a valid time, OverflowError is raised.

sleep (secs)
Suspend execution for the given number of seconds. The argument may be a floating point number to indicate a more precise sleep time. The actual suspension time may be less than that requested because any caught signal will terminate the sleep() following execution of that signal's catching routine. Also, the suspension time may be longer than requested by an arbitrary amount because of the scheduling of other activity in the system.

strftime (format, tuple)
Convert a tuple representing a time as returned by gmtime() or localtime() to a string as specified by the format argument. format must be a string.

The following directives can be embedded in the format string. They are shown without the optional field width and precision specification, and are replaced by the indicated characters in the strftime() result:

Directive  Meaning  Notes 
%a Locale's abbreviated weekday name.  
%A Locale's full weekday name.  
%b Locale's abbreviated month name.  
%B Locale's full month name.  
%c Locale's appropriate date and time representation.  
%d Day of the month as a decimal number [01,31].  
%H Hour (24-hour clock) as a decimal number [00,23].  
%I Hour (12-hour clock) as a decimal number [01,12].  
%j Day of the year as a decimal number [001,366].  
%m Month as a decimal number [01,12].  
%M Minute as a decimal number [00,59].  
%p Locale's equivalent of either AM or PM.  
%S Second as a decimal number [00,61]. (1)
%U Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0.  
%w Weekday as a decimal number [0(Sunday),6].  
%W Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0.  
%x Locale's appropriate date representation.  
%X Locale's appropriate time representation.  
%y Year without century as a decimal number [00,99].  
%Y Year with century as a decimal number.  
%Z Time zone name (or by no characters if no time zone exists).  
%% A literal "%" character.  

Notes:

(1)
The range really is 0 to 61; this accounts for leap seconds and the (very rare) double leap seconds.

Additional directives may be supported on certain platforms, but only the ones listed here have a meaning standardized by ANSI C.

On some platforms, an optional field width and precision specification can immediately follow the initial "%" of a directive in the following order; this is also not portable. The field width is normally 2 except for %j where it is 3.

strptime (string[, format])
Parse a string representing a time according to a format. The return value is a tuple as returned by gmtime() or localtime(). The format parameter uses the same directives as those used by strftime(); it defaults to "%a %b %d %H:%M:%S %Y" which matches the formatting returned by ctime(). The same platform caveats apply; see the local Unix documentation for restrictions or additional supported directives. If string cannot be parsed according to format, ValueError is raised. Values which are not provided as part of the input string are filled in with default values; the specific values are platform-dependent as the XPG standard does not provide sufficient information to constrain the result.

Note: This function relies entirely on the underlying platform's C library for the date parsing, and some of these libraries are buggy. There's nothing to be done about this short of a new, portable implementation of strptime().

Availability: Most modern Unix systems.

time ()
Return the time as a floating point number expressed in seconds since the epoch, in UTC. Note that even though the time is always returned as a floating point number, not all systems provide time with a better precision than 1 second.

timezone
The offset of the local (non-DST) timezone, in seconds west of UTC (i.e. negative in most of Western Europe, positive in the US, zero in the UK).

tzname
A tuple of two strings: the first is the name of the local non-DST timezone, the second is the name of the local DST timezone. If no DST timezone is defined, the second string should not be used.

See Also:

Module locale:
Internationalization services. The locale settings can affect the return values for some of the functions in the time module.

See About this document... for information on suggesting changes.