| Date::Manip::Date(3) | User Contributed Perl Documentation | Date::Manip::Date(3) |
NAME¶
Date::Manip::Date - Methods for working with dates
SYNOPSIS¶
use Date::Manip::Date; $date = new Date::Manip::Date;
DESCRIPTION¶
This module works specifically with date objects.
Although the word date is used extensively here, it is actually somewhat misleading. Date::Manip works with the full calendar date (year, month, day, and week when appropriate), time of day (hour, minute, second), and time zone. It doesn't work with fractional seconds.
METHODS¶
- base
- config
- err
- is_date
- is_delta
- is_recur
- new
- new_config
- new_date
- new_delta
- new_recur
- tz
- Please refer to the Date::Manip::Obj documentation for these methods.
- calc
-
$date2 = $date->calc($delta [,$subtract]); $delta = $date->calc($date2 [,$subtract] [,$mode]);Please refer to the Date::Manip::Calc documentation for details.
- cmp
-
$val = $date1->cmp($date2);This compares two different dates (both of which must be valid date objects). It returns -1, 0, or 1 similar to the cmp or <=> operators in perl. The comparison will automatically handle time zone differences between the two dates (i.e. they will be sorted in order as they appear in the GMT zone).
A warning is printed if either of the date objects does not include a valid date.
- complete
-
$flag = $date->complete([$field]);This tests the date stored in the object to see if it is complete or truncated (see below for a discussion of this).
If no $field is passed in, it returns 1 if the date is complete, or 0 if it was truncated and default values have been supplied.
If $field is passed in, it may be one of: m, d, h, mn, s . It will return 1 if the value for that field was specified, or 0 if a default was used.
- convert
-
$err = $date->convert([$zone]);This converts the date stored in the object to a different time zone. $zone can be the name of a time zone. If it is not passed in, the date is converted to the local time zone.
- holiday
-
$name = $date->holiday(); $name = $date->event();This returns the name of the holiday if $date is a holiday. If $date is not a holiday, undef is returned. If $date is an unnamed holiday, an empty string is returned.
- input
-
$str = $date->input();This returns the string that was parsed to form the date.
- is_business_day
-
$flag = $date->is_business_day($checktime);This returns 1 if $date is a business day.
$checktime may be passed in. If it is non-zero, the time is checked to see if the date is a business day and falls within work hours.
- list_holidays
-
@date = $date->list_holidays([$y]);This returns a list of Date::Manip::Date objects containing all dates during a year which are holidays. The times will all be 00:00:00.
If $y is not passed in, it will list the holidays in the same year as the date stored in $date.
- list_events
-
@list = $date->list_events( [$format] ); @list = $date->list_events(0 [,$format]); @list = $date->list_events($date1 [,$format]);This returns a list of events. Events are defined in the Events section of the config file (discussed in the Date::Manip::Holidays manual).
In the first form, a list of all events active at the precise time stored in $date will be returned.
If the first argument evaluates to 0, a list of all events active at any time during that day (Y,M,D) are returned.
If the first argument is another date object, all events that are active at any time between the two dates (inclusive) are returned.
By default, the list returned is of the form:
( [START, END, NAME], [START, END, NAME], ... )where START is a date object when an event starts, END is a date object when it ends, and NAME is the name of the event. Note that START and END are the actual start and end date of the event and may be outside the range of dates being examined (though the event will obviously overlap the range or it wouldn't be included in the list).
If $format is included, it can specify an alternate format for the output. Currently, the only supported format is named "dates" and it returns a list in the form:
( [DATE1, NAME1a, NAME1b, ...], [DATE2, NAME2a, NAME2b, ...], ... )This includes a list of all dates during the range when there is a change in what events are active. DATE1 will always be the start of the range being considered, and (NAME1a, NAME1b, ...) are the list of all events that will be active at that time. At DATE2, the list of active events changes with (NAME2a, NAME2b, ...) being active.
It is quite possible that a date be included which has no active events, and in that case, the list of names will be empty.
- nearest_business_day
-
$date->nearest_business_day([$tomorrowfirst]);This looks for the work day nearest to $date. If $date is a work day, it is left unmodified. Otherwise, it will look forward or backwards in time 1 day at a time until a work day is found. If $tomorrowfirst is non-zero (or if it is omitted and the config variable TomorrowFirst is non-zero), we look to the future first. Otherwise, we look in the past first. In other words, in a normal week, if $date is Wednesday, $date is returned. If $date is Saturday, Friday is returned. If $date is Sunday, Monday is returned. If Wednesday is a holiday, Thursday is returned if $tomorrowfirst is non-nil or Tuesday otherwise.
- next_business_day
- prev_business_day
-
$date->next_business_day($off [,$checktime]); $date->prev_business_day($off [,$checktime]);The next_business_day method sets the given date to $off (which can be a positive integer or zero) business days in the future. The prev_business_day method sets the date to $off business days in the past.
First, $date is tested. If $checktime is nonzero, the date must fall on a business date, and during business hours. If $checktime is zero, the time check is not done, and the date must simply fall on a business date.
If the check fails, the date is moved to the start of the next business day (if $checktime is nonzero) or the next business day at the current time (if $checktime is zero). Otherwise, it is left unmodified.
Next, if $off is greater than 0, the day $off work days from now is determined.
One thing to note for the prev_business_day method is that if $date check fails, the date is set to the next business date, exactly like next_business_day. In other words, if $date is not a business day, the call:
$date->prev_business_day(0 [,$checktime]);moves $date forward in time instead of backward which is nonintuitive, but you just have to think of day 0 as being the next business day if $date is not a business day.
As a result, the following two calls ALWAYS give the same result:
$date->next_business_day(0 [,$checktime]); $date->prev_business_day(0 [,$checktime]);no matter what date is stored in $date.
- parse
-
$err = $date->parse($string [,@opts]);This parses a string which should include a valid date and stores it in the object. If the string does not include a valid date, an error is returned. Use the err method to see the full error message.
A full date may include a calendar date (year, month, day), a time of day (hour, minute, second), and time zone information. All of this can be entered in many different formats.
For information on valid date formats, refer to the section VALID DATE FORMATS. For information on valid time zone information, refer to the section VALID TIME ZONE FORMATS.
If no time zone information is included in the date, it is treated as being in the local time zone.
If time zone information is included, the date will be kept in that time zone, and all operations will be done in that time zone. The convert method can be used to change the time zone to the local time zone, or to another time zone.
Some things to note:
All strings are case insensitive. "December" and "DEceMBer" are equivalent.
When a part of the date is not given, defaults are used. This is described below in the section "Complete vs. truncated dates and times".
The year may be entered as 2 or 4 digits. If entered as 2 digits, it will be converted to a 4 digit year. There are several ways to do this based on the value of the YYtoYYYY config variable. Refer to the Date::Manip::Config documentation for more details.
Dates are always checked to make sure they are valid.
If any other arguments are passed in, they act as options which may improve the speed of parsing. These include:
noiso8601 Do not try to parse the date as an ISO 8601 date or time. nodow Do not try to parse a day-of-week (Monday) in the string. nocommon Do not try to parse the date using the formats in the "Common date formats" section. noother Do not try to parse the date using the "Less common date formats" or a time using the "Other time formats". nospecial Do not try to parse the date using the "Special date strings" formats or a time using the "Special time strings" formats, or as a combined date/time using the "Additional combined date and time" formats. nodelta Do not treat deltas as a date relative to now. - parse_date
-
$err = $date->parse_date($string [,@opts]);This parses a string which contains a valid date and sets the date part of the object.
If the object contained a valid date, the time is kept unchanged. If the object did NOT contain a valid date, a time of 00:00:00 is used.
@opts can be any of the strings described in the parse method above.
- parse_time
-
$err = $date->parse_time($string);This parses a string and sets the time portion of $date to contain it.
If the object contained a valid date, the Y/M/D portion is left unchanged. Otherwise, the current date is used.
- parse_format
-
$err = $date->parse_format($format,$string);This will parse a date contained in $string based on explicit format information contained in $format.
If the format is invalid, $err will contain an error message. If the format is valid, but string doesn't match, an error code of 1 is returned.
$format is a string containing a regular expression with some special directives (based on the printf directives). These directives are turned into regular expression components, and then the entire string is turned into a regular expression which, if $string matches it, will return the date.
The directives available are identical to the printf directives. So, if your $format string contains the directive '%Y', it will match a 4-digit year.
All of the printf directives are available, but with a few simplifications:
%l This directive is NOT available. %b,%h,%B will all match a month name or abbreviation %v,%a,%A will all match a day abbreviation or name %z,%Z,%N will match any time zone string %n currently not allowed (multi-line matching not currently supported)The format string may not over-specify the date. In other words, you may not include both a %y and %Y directive or both a %j and %m directive.
A valid format string will specify any of the following sets of data:
Required Optional M D H Mn S Y Zone Day-of-week M D H Mn Y Zone Day-of-week M D Y Zone Day-of-week H Mn S Zone H Mn ZoneFor example, if you had a date stored as:
YYYY.MM-DDyou could match it using the following:
$date->parse_format('%Y\\.%m\\-%d',$string);If you wanted to extract the date from an apache log line:
10.11.12.13 - - [17/Aug/2009:12:33:30 -0400] "GET /favicon.ico ...you could use:
$date->parse_format('.*?\\[%d/%b/%Y:%T %z\\].*',$line);In your format string, you may use capture buffers that can be back referenced elsewhere in the regular expression. If you use numbered back references, just be aware that all of the directives create a single capture buffer (except for the directives like %% which match a special character instead of a portion of a date). If you use named buffers, do NOT use any of the following as they will conflict with the capture buffers created with the standard directives:
y m d h mn s mon_name mon_abb dow_name dow_abb dow_char dow_num doy nth ampm epochs epocho tzstring off abb zone g w l uTo be safe, it is suggested that named capture buffers start with a capital letter.
There is one other caveat if the %x directive is used. The format is converted to a regular expression and then cached (so that a format can be reused without the penalty of doing the conversion to a regular expression, so if you need to set the DateFormat config variable (which determines the meaning of the %x directive), it must be done before a format string containing %x is used. If the DateFormat config variable is set afterwards, the format string will reflect the old, NOT THE NEW, value of DateFormat.
- prev
- next
- The prev method changes the date to the previous (or current) occurrence
of either a day of the week, a certain time of day, or both. The next
method changes the date to the next (or current) occurrence. The examples
below illustrate the prev method, but the next one is identical in
operation.
There are two different ways to use this method. The first is to pass in a day of week and possibly a time:
$err = $date->prev($dow, $curr [,$time]);If $curr = 0, this means to look for the previous occurence of the day of week, and set the time to the value passed in (or current time if no time was passed in). The day is ALWAY less than the current day. If the current day is the same day of week as $dow, then the date returned will be one week earlier.
If $curr = 1, it means to look for the current or previous occurence of the day of week, and set the time to the value passed in (or 00:00:00 if none was passed in). If the current day of week is the same as $dow, the date will remain unchanged. Since the time is then set, the new date may actually occur after the original date depending on the value of $time.
If $curr = 2, it means to look for the last time (not counting now) that the day of week at the given time occurred. The date may be the same as the original date.
$time may be a list reference of [H,MN,S], [H,MN], or [H].
The following examples should illustrate the use of this function.
Original Date = Fri Nov 22 18:15:00 dow curr time new date 4 (Thu) 0/1/2 undef Thu Nov 21 00:00:00 4 0/1/2 [12,30,0] Thu Nov 21 12:30:00 5 (Fri) 0/2 undef Fri Nov 15 18:15:00 5 1 undef Fri Nov 22 18:15:00 5 0 [12,30,0] Fri Nov 15 12:30:00 5 1/2 [12,30,0] Fri Nov 22 12:30:00 5 0/2 [19,30,0] Fri Nov 15 19:30:00 5 1 [19,30,0] Fri Nov 22 19:30:00The second way to use this method is by passing in undef for the day of week.
$err = $date->prev(undef,$curr,$time);In this case, a time is required and it must be a list reference of 3 elements: [H, MN, S]. Any or all of the elements may be undef.
The new date is the previous occurrence of the time.
If you define hours, then minutes and seconds may be defined, or default to 0 and you are looking for a previous time that the specified time (HH:00:00) occurred (which might be as much as 24 hours in the past).
If hours are undefined and minutes are defined, then seconds may be defined, or default to 0, and you are looking for the last time the minutes/seconds (MN:SS) appeared on the digital clock, which will be sometime in the past hour.
Finally, if hours and minutes are undefined, seconds must be defined (or default to zero) and the last time that that second occurred will be returned (which will be sometime in the past minute).
If $curr is non-zero, the current time is returned if it matches the criteria passed in, so the returned value will be now or in the past. If $curr is zero, the time returned will definitely be in the past.
DATE = Fri Nov 22 18:15:00 curr hr min sec returns 0/1 18 undef undef Nov 22 18:00:00 0/1 18 30 0 Nov 21 18:30:00 0 18 15 undef Nov 21 18:15:00 1 18 15 undef Nov 22 18:15:00 0 undef 15 undef Nov 22 17:15:00 1 undef 15 undef Nov 22 18:15:00 - printf
-
$out = $date->printf($in); @out = $date->printf(@in);This takes a string or list of strings which may contain any number of special formatting directives. These directives are replaced with information contained in the date. Everything else in the string is returned unmodified.
A directive always begins with '%'. They are described in the section below in the section PRINTF DIRECTIVES.
- secs_since_1970_GMT
-
$secs = $date->secs_since_1970_GMT();This returns the number of seconds that have elapsed since Jan 1, 1970 00:00:00 GMT (negative if the date is earlier).
The reverse is also allowed:
$err = $date->secs_sincs_1970_GMT($secs);which sets the date to $secs seconds from Jan 1, 1970 00:00:00 GMT in the local time zone.
- set
-
$err = $date->set($field,@vals [,$isdst]);This explicitly sets one or more fields in a date.
$field can be any of the following:
$field @vals zone [ZONE] ZONE can be any zone or alias zdate [ZONE,]DATE sets the zone and entire date date DATE sets the entire date time TIME sets the entire time y YEAR sets one field m MONTH d DAY h HOUR mn MINUTE s SECONDHere, DATE is a list reference containing [Y,M,D,H,MN,S] and TIME is a list reference containing [H,MN,S].
ZONE is optional (it defaults to the local zone as defined either by the system clock, or the SetDate or ForceDate config variables). If it is passed in, it can be any zone name, abbreviation, or offset. An offset can be expressed either as a valid offset string, or as a list reference. Refer to the join/split functions of Date::Manip::Base for information on valid offset strings.
An optional last argument is $isdst (which must be 0 or 1) is included when setting a date which could be in either standard time or daylight saving time. It is ignored in all other situations. If it is not included, and the resulting date could be in either, it will default to standard time.
The $date object must contain a valid date (unless the entire date is being set with $field set to either "zdate" or "date").
If $field is "zone", the time zone of the date will be set. If ZONE is not passed in, it will be set to the local time zone. When setting the time zone, no conversion is done! Whatever date and time is stored in the $date object prior to this remains unchanged... except it will be that date and time in the new time zone.
If $field is "zdate", the entire date and time zone is set. If ZONE is not passed in, it is set to the local time zone.
If $field is "date", the entire date will be set, but the time zone of the date will not be changed.
If $field is "time", or one of the individual fields, only those fields will be modified.
An error is returned if an invalid argument list is passed in, or if the resulting date is checked and found to be invalid.
- value
-
$val = $date->value([$type]); @val = $date->value([$type]);These return the value of the date stored in the object.
In scalar context, a printable string in the form YYYYMMDDHH:MN:SS is returned. In list context, a list is returned of (Y,M,D,H,MN,S).
If $type is omitted, the date is returned in the time zone it was parsed in.
If $type is "local", it is returned in the local time zone (which is either the system time zone, or the zone specified with the SetDate or ForceDate config variables).
If $type is "gmt", the date is returned in the GMT time zone.
An empty string or list is returned i the case of an error (and an error code is set).
- week_of_year
-
$wkno = $date->week_of_year([$first]);This figures out the week number. If $first is passed in, it must be between 1 and 7 and refers to the first day of the week. If $first is not passed in, the FirstDay config variable is used.
NOTE: This routine should only be called in rare cases. Use printf with the %W, %U, %J, %L formats instead. This routine returns a week between 0 and 53 which must then be "fixed" to get into the ISO 8601 weeks from 1 to 53. A date which returns a week of 0 actually belongs to the last week of the previous year. A date which returns a week of 53 may belong to the first week of the next year.
ISSUES WITH PARSING DATES¶
The following issues may occur when parsing dates that should be understood to make full use of this module.
- Complete vs. truncated dates and times
- Date formats are either complete or truncated. A complete date fully
specifies the year, month, and day and a complete time fully specifies the
hour, minute, and second.
It should be understood that in many instances, the information may be implied rather than explicitly stated, but it is still treated as complete.
For example, the date "January 3" is complete because it implies the current year.
A truncated calendar date or time does not include information about some of the fields. Date::Manip will never work with a partial date or time, so defaults will be supplied.
For example, the date "2009-01" is missing a day field, so a default will be used. In this case, the day will be the 1st, so this is equivalent to "Jan 1st 2009". If only the year is given, it will default to Jan 1.
If the time, or any of it's components is missing, they default to 00. So the time "12:30" and "12:30:00" are equivalent.
The "complete" method can be used to check what type of date was parsed, and which values were specified (either explicitly or implied) and which were provided as a default. It should be noted that there is no way to differentiate between an explicit and implied value.
A string with a date and/or time may consist of any of the following:
a complete date and a time (complete or truncated) a truncated date with no time a time (complete or truncated) with no dateIn other words, the date "Jan 2009 12:30" is not valid since it consists of a time with a truncated date.
VALID TIME ZONE FORMATS¶
When specifying a time zone, it can be done in three different ways. One way is to specify the actual time zone. The second is to supply a valid time zone abbreviation. The third is to specify an offset (with an optional abbreviation). The following dates illustrate the these formats.
The timezone information always follows the time immediately, and may only be included if a time is included. The following examples use an ISO 8601 format for the date/time, but any of the other date and time formats may be used.
The first way to specify the time zone is to specify it by complete name (or using one of the standard aliases):
2001-07-01-00:00:00 America/New_York
Although this is unambiguous when it comes to determining the time zone, the time is ambiguous in most zones for one hour of the year. When a time change occurs during which the clock is moved back, the same wallclock time occurs twice.
For example, in America/New_York, on Sunday, Nov 2, 2008, at 02:00 in the morning, the clock was set back to 01:00. As a result, the date Nov 2, 2008 at 01:30 is ambiguous. It is impossible to determine if this refers to the 01:30 that occurred half an hour before the time change, or the one 30 minute after the change.
In practice, if this form is used, the date will be assigned to standard time, meaning that there will be some times (typically 1 hour per year) which cannot be expressed this way. As such, this method is discouraged.
The second way to specify the time zone, which is the most common, is to use a time zone abbreviation:
2001-07-01-00:00:00 EDT
Unfortunately, the abbreviation does not uniquely determine the time zone except in a few cases. In order to assign a time zone, Date::Manip will refer to a list of all time zones which use the abbreviation. They will be tested, in the order given in the Date::Manip::Zones documentation, and the first match (i.e. the one in which the given date/time and abbreviation are valid) determines the time zone which will be used. A great deal of effort has been made to ensure that the most likely time zone will be obtained (i.e. the most common time zones are tested before less common ones), so in most cases, the desired results will be obtained.
If the default order does not yield the desired time zone, the order of testing can be modified using the abbrev method described in the Date::Manip::TZ documentation.
Although the time zone is ambiguous, the date is not, since only time zones for which the date are valid will be used.
The third way to specify the time zone is by specifying an offset and an optional abbreviation:
2001-07-01-00:00:00 -04 2001-07-01-00:00:00 -0400 2001-07-01-00:00:00 -040000 2001-07-01-00:00:00 -04:00 2001-07-01-00:00:00 -04:00:00 2001-07-01-00:00:00 -04 (EDT) 2001-07-01-00:00:00 -0400 (EDT) 2001-07-01-00:00:00 -040000 (EDT) 2001-07-01-00:00:00 -04:00 (EDT) 2001-07-01-00:00:00 -04:00:00 (EDT)
The offset almost never sufficient to uniquely determine the time zone (and it is not even guaranteed that both the offset and abbreviation will, though in practice, it is probably sufficient). In this instance, the time zone will be determined by testing all time zones which have the given offset (and abbreviation if it is included) until one is found which matches both pieces of information. For more information about how this testing is done, refer to the def_zone method of the Date::Manip::TZ documentation.
VALID DATE FORMATS¶
There are several categories of date formats supported by Date::Manip. These are strings which specify only the year/month/day fields.
These formats explicitly set the date, but not the time. These formats may be combined with a time string (as specified below) to set both the date and time. If this is not done, the default time is determined by the DefaultTime config variable.
- ISO 8601 dates
- The preferred date formats are those specified by ISO 8601. The
specification includes valid calendar date and valid time formats.
Date::Manip will handle all of these formats, but does not require that
the dates rigidly adhere to the specification since the ultimate goal of
Date::Manip is to handle dates as they are represented in real life and
some common variations exist which are similar to, but not identical to,
those from the specification.
A calendar date includes the following fields:
CC 2-digit representation of the century YY 2-digit representation of the year in a century MM 2-digit representation of a month DD 2-ditit representation of a day of month DoY 3-digit representation of a day of year (001-366) Www the character "W" followed by a 2-digit week of the year (01-53) D the day of the week (1-7)The following date formats are considered complete by Date::Manip. In the following, the date Thu Mar 5 2009 is used as an example. This is the 64th day of the year. Thu is the 4th day of the week. The week starting Mon, Mar 2 is the 10th week of the year (according the the ISO 8601 definition). Obviously, some of the formats are only valid when used at some times. For example, the format --MMDD refers to a month and day in the current year, so the date Mar 5, 2009 can only be specified using this format during 2009.
Format Notes Examples CCYYMMDD 20090305 CCYY-MM-DD 2009-03-05 YYMMDD 1,2,4 090305 YY-MM-DD 09-03-05 -YYMMDD 3,4 -090305 -YY-MM-DD -09-03-05 --MMDD 1 --0305 --MM-DD --03-05 ---DD 1 ---05 CCYYDoY 2009064 CCYY-DoY 2009-064 YYDoY 1,4 09064 YY-DoY 09-064 -YYDoY 3,4 -09064 -YY-DoY -09-064 -DoY 1 -064 CCYYWwwD 2009W104 CCYY-Www-D 2009-W10-4 YYWwwD 1,4 09W104 YY-Www-D 09-W10-4 -YYWwwD 3,4 -09W104 -YY-Www-D -09-W10-4 -YWwwD 1 -9W104 -Y-Www-D -9-W10-4 Y is the year (0-9) in current decade -WwwD 1 -W104 -Www-D -W10-4 -W-D 1 -W-4 D is day (1-7) in current week ---D 1 ---4 same as -W-DThe following date formats are truncated:
CCYY-MM 2 2009-03 CCYY 2009 CC 2 20 -YYMM 4 -0903 -YY-MM -09-03 -YY 4 -09 --MM --03 CCYYWww 2009W10 CCYY-Www 2009-W10 YYWww 4 09W10 YY-Www 09-W10 -YYWww 3,4 -09W10 -YY-Www -09-W10 -Www -W10Notes:
1 These formats are considered truncated in the standard, but since
they do include (or imply, using the current date for defaults) all of
the fields, and since they do not introduce any parsing complexities,
the standard is relaxed, and they are treated as complete.2 These formats are treated differently than in Date::Manip 5.xx as
described below.3 These formats are not defined in the ISO 8601 spec, but
are added for the sake of completeness since they do not
add any parsing incompatibilities.4 Formats where the century is not given are described as a year in
the current century in the specification. Date::Manip treats this
more generically using the YYtoYYYY config variable. This will be
used to determine how to determine the full year.Date::Manip 5.xx handled ISO 8601 dates in a less rigid fashion, and deviated from the specification in several formats. As of 6.00, the specification is followed much more closely so that all of the date formats included in it should produce valid dates. This changes, in a backwards incompatible way, the way a few strings will be interpreted as dates.
As of 6.00, a two-digit date will be treated as CC. Previously, it was treated as YY.
A six-digit date will be treated as YYMMDD. Previously, it was treated as YYYYMM.
Previously, dashes were treated as optional in many cases. According to the specification, dates may be written in expanded form (with all dashes present) or abbreviate form (with no dashes). As of 6.00, this is the behavior, so the formats: YYMMDD and YY-MM-DD are allowed, as per the specification, but the format YY-MMDD is NOT allowed (though it was previously).
The Www-D formats require a bit of explanation. According to the specification, the date:
1996-w02-3refers to the day with an ordinal number of 3 within the calendar week in the 2nd week of 1996.
In the specification, the days of the week are numbered from 1 to 7 (Monday to Sunday), and the week always begins on Monday, so day 1 (Monday) is always the first day of the week, day 2 (Tuesday) is always the second day of the week, etc.
In Date::Manip, the constraint that the week must start with Monday is relaxed, allowing the week to begin with Sunday (a far more common start of the week in calendars, at least in some parts of the world).
This presents a problem though in that the above date could be interpreted as Wednesday (day 3) of the 2nd week of 1996, or as the 3rd day of the 2nd week of 1996 (which would normally be Wednesday, but would be Tuesday if the week begins on Sunday).
As of Date::Manip 6.00, the above date will be interpreted as the 3rd day of the 2nd week. This is a reversal from Date::Manip 5.xx, but I believe is what the specification would require. For more information, refer to the Date::Manip::Changes document.
- Common date formats
- Date::Manip supports a number of common date formats. The following fields
may be included in a date:
YY 2-digit representation of the year YYYY 4-digit representation of the year M 1- or 2- digit representation of the month MM 2-digit representation of the month D 1- or 2- digit representation of the day DD 2-digit representation of the day mmm The abbreviated or full month name (i.e. Jan)The following date formats are supported:
Format Notes Examples M/D 1,2 3/5 M/D/YY 1 3/5/09 M/D/YYYY 1 3/5/2009 YYYY/M/D 2009/3/5 mmm/D Mar/5 mmm/D/YY Mar/5/09 mmm/D/YYYY Mar/5/2009 D/mmm 5/Mar D/mmm/YY 5/Mar/09 D/mmm/YYYY 5/Mar/2009 YYYY/mmm/D 2009/Mar/5 mmmD Mar5 mmmDDYY Mar0509 mmmDDYYYY Mar052009 Dmmm 5Mar DmmmYY 5Mar09 DmmmYYYY 5Mar2009 YYYYmmmD 2009Mar5 mmmD YY Mar5 09 mmmD YYYY Mar5 2009 Dmmm YY 5Mar 09 Dmmm YYYY 5Mar 2009 mmm/D YY Mar/5 09 mmm/D YYYY Mar/5 2009 D/mmm YY 5/Mar 09 D/mmm YYYY 5/Mar 2009 YY mmmD 09 Mar5 YYYY mmmD 2009 Mar5 YY Dmmm 09 5Mar YYYY Dmmm 2009 5Mar YY mmm/D 09 Mar/5 YYYY mmm/D 2009 Mar/5 YY D/mmm 09 5/Mar YYYY D/mmm 2009 5/Mar YYYY:MM:DD 2010:01:15 (EXIF format)In the formats above, the slash (/) can be replace by any of the valid separators: whitespace, slash (/), period (.), or dash (-). The dash, though allowed, is discouraged since it may conflict with an ISO 8601 format. For example, the format MM/DD/YY is just fine, but MM-DD-YY does not work since it conflicts with YY-MM-DD. To be safe, if "-" is used as a separator in a non-ISO format, they should be turned into "/" before calling the Date::Manip routines.
No matter what separator is used, the same separator must be used throughout the date. For example, MM/DD/YY is valid and MM.DD.YY is also valid, but MM/DD.YY is NOT valid.
Notes:
1 With these formats, Americans tend to write month first, but many
other countries tend to write day first. The latter behavior can be
obtained by setting the config variable DateFormat to something other
than "US".2 The dot (.) separator may not be used in the M/D format since it
will be interpreted as the H12,H+ format described below.These formats explicitly set the date, but not the time. The default time is determined by the DefaultTime config variable.
- Less common date formats
- The following formats are also supported by Date::Manip:
DoW The day of week of the current week Friday Friday at 12:40 MMM Nth [YYYY] Nth MMM [YYYY] YYYY MMM Nth YYYY Nth MMM Dec 1st 1970 1st Dec 1970 1970 Dec 1st 1970 1st Dec next/prev DoW The next or last occurence of DoW next Friday last Friday at 12:40 next/last week/month/year The day one week/month/year from now or in the past next week last month at 15:00 last day in MMM [YYYY] The last day of the month last day in October last day in October 1996 last DoW in MMM [YYYY] The last DoW in the month last Tuesday in October last Tuesday in October 1996 last DoW in YYYY The last DoW in the year last Tuesday in 1997 NOTE: "last DoW" doesn't work in English since the word "last" is used for both this expression and for "prev DoW", which gets parsed first. "last DoW" MAY work in other languages. Nth DoW in MMM [YYYY] The Nth DoW in the month 3rd Tuesday in October 3rd Tuesday in October 1996 Nth DoW [YYYY] The Nth DoW in the year 22nd Sunday 22nd Sunday in 1996 DoW week British: same as "in 1 week on DoW" Monday week DoW week N [YYYY] Dow Nth week [YYYY] Sunday week 22 Sunday 22nd week These refer to the day of week of the Nth week of the year. Nth 12th This refers to the Nth day of the current month.Note that the formats "Sunday week 22" and "22nd Sunday" give different behaviors. "Sunday week 22" returns the Sunday of the 22nd week of the year based on how week 1 is defined. ISO 8601 defines week one to contain Jan 4, so "Sunday week 1" might be the first or second Sunday of the current year, or the last Sunday of the previous year. "22nd Sunday" gives the actual 22nd time Sunday occurs in a given year, regardless of the definition of a week.
- Special date strings
- Most languages have strings which can be used to specify the date
(relative to today). In English, these include the strings:
today tomorrow yesterdayThere is also support for the British formats:
today week tomorrow week yesterday weekwhich refer to one week after today/tomorrow/yesterday respectively.
Other languages have similar strings.
In all of the formats (except for ISO 8601 formats), the day of week ("Friday") can be entered anywhere in the date and it will be checked for accuracy. In other words,
"Tue Jul 16 1996 13:17:00"
will work but
"Jul 16 1996 Wednesday 13:17:00"
will not (because Jul 16, 1996 is Tuesday, not Wednesday).
VALID TIME FORMATS¶
There are several categories of time formats supported by Date::Manip. These are strings which specify only the hour/minute/second fields.
- ISO 8601 times
- A time may be also be complete or truncated. Again, Date::Manip treats
some formats as complete even though the specification calls them
truncated.
A time may include the following fields:
HH 2-digit representation of the hour MN 2-digit representation of the minutes SS 2-digit representation of the seconds H+ 1+ digit representation of fractional hours M+ 1+ digit representation of fractional minutes S+ 1+ digit representation of fractional secondsThe following time formats are considered complete by Date::Manip. The time 12:30:15 will be expressed in the examples.
Format Notes Examples HHMNSS 2 123015 HH:MN:SS 12:30:15 HHMNSS,S+ 123015,5 HH:MN:SS,S+ 12:30:15,5 Fractional seconds are ignored HHMN,M+ 1230,25 HH:MN,M+ 12:30,25 This is 12:30:00 + 0.25 minutes HH,H+ 12,5 This is 12:00:00 + 0.5 hours, so this is equivalent to 12:30:00 -MNSS 1 -3015 -MN:SS -30:15 --SS 1 --15 -MNSS,S+ 1 -3015,5 -MN:SS,S+ -30:15,5 -MN,M+ 1 -30,25 --SS,S+ 1 --15,5 HHMN 3 1230 HH:MN 12:30The following time formats are truncated:
HH 12 -MN -30Notes:
1 These formats are considered truncated in the standard, but since
they do include (or imply, using the current time for defaults) all of
the fields, and since they do not introduce any parsing complexities,
the standard is relaxed, and they are treated as complete.2 The HHMNSS format will not be correctly parsed since it is impossible
to distinguish between it and YYMMDD. In order to parse an all-digit
time, add the string ",0" to the end to force it to be interpreted
as a time or include time zone information (either a zone name or
abbreviation... an offset will not work in this case).3 The HH:MN format will be treated as complete, even though it is
incomplete due to missing the seconds. In real life, expressing
a time in the HH:MN format is very common, and is regarded as complete,
and might include time zone information.ISO 8601 times may be followed by a time zone. Date::Manip relaxes the constraints placed on the time zone format and allows any of the methods used to specify the time zone including time zone name, abbreviation, or offset. The time zone may be separated from the time by a space, but it is not required.
Another constraint that is relaxed is that the fractional part may be specified using a period. In other words, the following are equivalent:
12:30,25 12:30.25It should be noted (as it is in the specification) that using a negative time zone offset may cause confusion. In addition to visually confusing, it may not be parsed correctly. For example, the time:
123005-0300may not be parsed correctly. When using an offset time zone, you should always use the colon separators in the time:
12:30:05-0300 - Other time formats
- A time may include any of the following fields:
H24 1- or 2-digit representation of the hour (0-23) H12 1- or 2-digit representation of the hour (1-12) MN 2-digit representation of the minutes SS 2-digit representation of the seconds H+ 1+ digit representation of fractional hours M+ 1+ digit representation of fractional minutes S+ 1+ digit representation of fractional seconds AM A language specific AM/PM stringThe following time formats are accepted:
Format Examples H24:MN:SS 17:30:15 H12:MN:SS AM 5:30:15 PM H12:MN:SS H24:MN:SS,S+ 17:30:15,5 H12:MN:SS,S+ AM 5:30:15,5 PM H12:MN:SS,S+ Fractional seconds are ignored H24:MN,M+ 17:30,25 H12:MN,M+ AM 5:30,25 PM H12:MN,M+ This is 17:30:00 + 0.25 minutes H24,H+ 17,5 H12,H+ AM 5,5 PM H12,H+ This is 17:00:00 + 0.5 hours, so this is equivalent to 17:30:00 H24:MN 17:30 H12:MN AM 5:30 PM H12:MN H12 AM 5 PMThe fractional part may be specified using a comma, a period, or a colon. A language specific fractional separator may also be available for some languages. A colon will only work if the hour, minute, and second are all explicitly included, but will not work otherwise.
In other words, the following are equivalent:
12:30:20,25 12:30:20.25 12:30:20:25Some languages have alternate H:MN and MN:S separators. For example, one H:MN separator in French is 'h' (the MN:S separator is still a colon), so the following are equivalent:
12:30:00 12h30:00Time zone information can be included immediately following the time. It can be separated by whitespace from the time, or it can be immediately adjacent.
- Special time strings
- Different languages may have some words which can be used to specify a
certain time of day. In English, for example, the following words are
equivalent to the time listed:
noon 12:00:00 midnight 00:00:00So, the following are equivalent:
Jan 2 2009 at noon Jan 2 2009 12:00:00There were two possible ways to interpret midnight. One was at the start of the day (00:00:00) and the other was at the end of the day (24:00:00 which would actually mean at 00:00:00 of the following day). The first has been used to maintain backwards compatibility with Date::Manip 5.xx .
Other languages have similar strings.
In most languages, a word similar to "at" may precede the time (this does NOT apply to ISO 8601 time formats). This word (which must be separate from all other parts of the date with whitespace) is optional, and the following are equivalent:
12:30 at 12:30
The times "12:00 am", "12:00 pm", and "midnight" are not well defined. Date::Manip uses the following convention:
midnight = 12:00am = 00:00:00 noon = 12:00pm = 12:00:00
and the day goes from 00:00:00 to 23:59:59. In other words, midnight is the beginning of a day rather than the end of one. The time 24:00:00 is also allowed (though it is automatically transformed to 00:00:00 of the following day). This gives the unusual result of parsing:
Wed Feb 8 2006 24:00:00
which gives the date of:
Thu Feb 9 2006 00:00:00
VALID COMBINED DATE AND TIME FORMATS¶
There are several categories of strings which specify both the date and time. These include the following:
- ISO 8601 combined date and time
- A combined ISO 8601 date and time is a string containing a complete ISO
8601 date and a complete or truncated ISO 8601 time.
Date::Manip relaxes the restrictions on how the two are combined. The time may be separated from the date by space, dash, or the letter T, or the two may be joined with nothing separating them.
When the time immediately follows the date, or when the two are separated by a dash, the resulting string MUST be unambiguous. Provided the date includes all of the dashes in it (i.e. YY-MM-DD instead of YYMMDD), it is rare that there is any ambiguity. If the date does not include dashes, the strings may be ambiguous, and in this case, separating the date and time with a space or the letter T is useful (and perhaps necessary) to correctly interpret the string.
The DoY formats should always be separated from the time by something. They are visually confusing if they are not separated from the time.
Time zone information can be included immediately following a complete time. It may not be included if no time is given, or if a truncated time is included. The time zone may be separated from the time with whitespace, or it can be immediately adjacent to it (since the ISO 8601 specification allows it in some cases).
- Non-ISO 8601 combined date and time
- A date from any of the formats above (except for the ISO 8601 formats) may be combined with any of the time formats above (except for the ISO 8601 time formats) in any combination to form a valid combined date and time.
- Deltas
- Dates are often specified in terms of a delta from "now". For
example, "in 2 days".
Any valid delta can be used to specify a date, and the date is defined as that delta added to "now". Refer to the Date::Manip::Delta documentation for a list of valid delta formats.
If the delta itself does not include a time part, the time may be specified explicitly. For example:
in 3 days at 12:00:00will take the delta part "in 3 days" and add it to the current time, then set the time to 12:00:00.
It is NOT allowed to include an explicit time if any time segment was included in the delta. For example, the following is invalid:
in 3 days 2 hours at 12:00:00One additional format that is supported is to include only week (or higher) components in the delta and to set the day of week. For example:
Friday in 2 weeks in 2 weeks on Friday Friday 2 weeks ago 2 weeks ago on Friday at 13:45These first apply the delta (of weeks, months, and years) to the current time, and then set the day to the given day-of-week in that week.
- Special date and time strings
- Most language have strings which can be used to specify the full date and
time (relative to the current date and time). In English, these include
the string:
now - Addition combined date and time formats
- The following formats are also supported:
epoch SECS The number of seconds since the epoch (Jan 1, 1970 00:00:00 GMT). SECS may be negative to give time before the epoch.
A couple of notes:
Commas may be included in all date formats arbitrarily (except for ISO 8601 formats where they may only be included when allowed by the specification).
The time/time zone is removed from the date before the date is parsed, so the time may appear before or after the date, or between any two parts of the date.
Certain words such as "on", "in", "at", "of", etc. which commonly appear in a date or time are ignored (except in ISO 8601 formats).
PRINTF DIRECTIVES¶
The following printf directives are replaced with information from the date.
Year
%y year - 00 to 99
%Y year - 0001 to 9999
Month, Week
%m month of year - 01 to 12
%f month of year - " 1" to "12"
%b,%h month abbreviation - Jan to Dec
%B month name - January to December
Day
%j day of the year - 001 to 366
%d day of month - 01 to 31
%e day of month - " 1" to "31"
%v weekday abbreviation - " S"," M"," T", ...
%a weekday abbreviation - Sun to Sat
%A weekday name - Sunday to Saturday
%w day of week - 1 to 7 (1=Monday)
%E day of month with
suffix - 1st, 2nd, 3rd...
Hour
%H hour - 00 to 23
%k hour - " 0" to "23"
%i hour - " 1" to "12"
%I hour - 01 to 12
%p AM or PM
Minute, Second, Time zone
%M minute - 00 to 59
%S second - 00 to 59
%Z time zone abbreviation - EDT
%z time zone as GMT offset - +0100 (see Note 4)
%N time zone as GMT offset - +01:00:00
Epoch (see NOTE 3 below)
%s seconds from
1/1/1970 GMT - negative if before
%o seconds from 1/1/1970
in the current time
zone
Date, Time
%c %a %b %e %H:%M:%S %Y - Fri Apr 28 17:23:15 1995
%C,%u %a %b %e %H:%M:%S %Z %Y - Fri Apr 28 17:25:57 EDT 1995
%g %a, %d %b %Y %H:%M:%S %Z - Fri, 28 Apr 1995 17:23:15 EDT
%D %m/%d/%y - 04/28/95
%x %m/%d/%y or %d/%m/%y - 04/28/95 or 28/04/28
(Depends on DateFormat variable)
%l date in ls(1) format (see NOTE 1 below)
%b %e %H:%M - Apr 28 17:23 (*)
%b %e %Y - Apr 28 1993 (*)
%r %I:%M:%S %p - 05:39:55 PM
%R %H:%M - 17:40
%T,%X %H:%M:%S - 17:40:58
%V %m%d%H%M%y - 0428174095
%Q %Y%m%d - 19961025
%q %Y%m%d%H%M%S - 19961025174058
%P %Y%m%d%H:%M:%S - 1996102517:40:58
%O %Y-%m-%dT%H:%M:%S - 1996-10-25T17:40:58
%F %A, %B %e, %Y - Sunday, January 1, 1996
%K %Y-%j - 1997-045
Special Year/Week formats (see NOTE 2 below)
%G year, Monday as first
day of week - 0001 to 9999
%W week of year, Monday
as first day of week - 01 to 53
%L year, Sunday as first
day of week - 0001 to 9999
%U week of year, Sunday
as first day of week - 01 to 53
%J %G-W%W-%w - 1997-W02-2
Other formats
%n insert a newline character
%t insert a tab character
%% insert a `%' character
%+ insert a `+' character
All other characters are currently unused, but may be used in the
future. They currently insert the character following the %,
If a lone percent is the final character in a format, it is ignored.
The formats used in this routine were originally based on date.pl (version 3.2) by Terry McGonigal, as well as a couple taken from different versions of the Solaris date(1) command. Also, several have been added which are unique to Date::Manip.
NOTE 1:
The ls format (%l) applies to date within the past OR future 6 months! Any date that is before the date NOW - 6 months, or that is on or after the date NOW + 6 months will have the year printed out.
The later time must be on or after so that there is no ambiguity. If it is now 2000-06-06-12:00:00, then the date 1999-12-06-12:00:00 will be written as "Dec 6 12:00" but the date 2000-12-06-12:00:00 will be written as "Dec 6 2000".
NOTE 2:
The %U, %W, %L, %G, and %J formats are used to support the ISO-8601 format: YYYY-wWW-D. In this format, a date is written as a year, the week of the year, and the day of the week. Technically, the week may be considered to start on any day of the week, but Sunday and Monday are the both common choices, so both are supported.
The %W and %G formats return the week-of-year and the year treating weeks as starting on Monday.
The %U and %L formats return the week-of-year and the year treating weeks as starting on Sunday.
Most of the time, the %L and %G formats returns the same value as the %Y format, but there is a problem with days occurring in the first or last week of the year.
The ISO-8601 representation of Jan 1, 1993 written in the YYYY-wWW-D format is actually 1992-W53-5. In other words, Jan 1 is treated as being in the last week of the preceding year. Depending on the year, days in the first week of a year may belong to the previous year, and days in the final week of a year may belong to the next year. The week is assigned to the year which has most of the days. For example, if the week starts on Sunday, then the last week of 2003 is 2003-12-28 to 2004-01-03. This week is assigned to 2003 since 4 of the days in it are in 2003 and only 3 of them are in 2004. The first week of 2004 starts on 2004-01-04.
The %U and %W formats return a week-of-year number from 01 to 53. %L and %G return the corresponding year, and to get this type of information, you should always use the (%W,%G) combination or (%U,%L) combination. %Y should not be used as it will yield incorrect results.
%J returns the full ISO-8601 format (%G-W%W-%w).
NOTE 3:
The %s and %o formats return negative values if the date is before the start of the epoch. Other Unix utilities would return an error, or a zero, so if you are going to use Date::Manip in conjunction with these, be sure to check for a negative value.
NOTE 4:
The %z format returns the offset in the RFC 822 specified format +0500 . Most offsets are full hour amounts, so this is not a problem, but some offsets are irregular (+05:17:30). In this case, the string returned is +051730 which isn't RFC 822 compliant, but since RFC 822 ignores this situation, I had to decide between returning an incorrect value, or breaking strict compliance, and I chose the second option.
KNOWN BUGS¶
None known.
BUGS AND QUESTIONS¶
Please refer to the Date::Manip::Problems documentation for information on submitting bug reports or questions to the author.
SEE ALSO¶
Date::Manip - main module documentation
LICENSE¶
This script is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
AUTHOR¶
Sullivan Beck (sbeck@cpan.org)
| 2011-12-10 | perl v5.10.1 |