Date manipulation
From Rosetta Code
You are encouraged to solve this task according to the task description, using any language you may know.
Given the date string "March 7 2009 7:30pm EST", output the time 12 hours later in any human-readable format.
As extra credit, display the resulting time in a time zone different from your own.
Contents |
[edit] AppleScript
AppleScript has a built-in date class and can coerce a string to a date automatically. It also has reserved constants such as hours which are defined in the unit of seconds. There is no built-in support for time zones.
set x to "March 7 2009 7:30pm EST"
return (date x) + 12 * hours
Result is:
date "Sunday, March 8, 2009 7:30:00 AM"
[edit] AutoHotkey
DateString := "March 7 2009 7:30pm EST"
; split the given string with RegExMatch
Needle := "^(?P<mm>\S*) (?P<d>\S*) (?P<y>\S*) (?P<t>\S*) (?P<tz>\S*)$"
RegExMatch(DateString, Needle, $)
; split the time with RegExMatch
Needle := "^(?P<h>\d+):(?P<min>\d+)(?P<xm>[amp]+)$"
RegExMatch($t, Needle, $)
; convert am/pm to 24h format
$h += ($xm = "am") ? 0 : 12
; knitting YYYYMMDDHH24MI format
_YYYY := $y
_MM := Get_MonthNr($mm)
_DD := SubStr("00" $d, -1) ; last 2 chars
_HH24 := SubStr("00" $h, -1) ; last 2 chars
_MI := $min
YYYYMMDDHH24MI := _YYYY _MM _DD _HH24 _MI
; add 12 hours as requested
EnvAdd, YYYYMMDDHH24MI, 12, Hours
FormatTime, HumanReadable, %YYYYMMDDHH24MI%, d/MMM/yyyy HH:mm
; add 5 hours to convert to different timezone (GMT)
EnvAdd, YYYYMMDDHH24MI, 5, Hours
FormatTime, HumanReadable_GMT, %YYYYMMDDHH24MI%, d/MMM/yyyy HH:mm
; output
MsgBox, % "Given: " DateString "`n`n"
. "12 hours later:`n"
. "(" $tz "):`t" HumanReadable "h`n"
. "(GMT):`t" HumanReadable_GMT "h`n"
;---------------------------------------------------------------------------
Get_MonthNr(Month) { ; convert named month to 2-digit number
;---------------------------------------------------------------------------
If (Month = "January")
Result := "01"
Else If (Month = "February")
Result := "02"
Else If (Month = "March")
Result := "03"
Else If (Month = "April")
Result := "04"
Else If (Month = "May")
Result := "05"
Else If (Month = "June")
Result := "06"
Else If (Month = "July")
Result := "07"
Else If (Month = "August")
Result := "08"
Else If (Month = "September")
Result := "09"
Else If (Month = "October")
Result := "10"
Else If (Month = "November")
Result := "11"
Else If (Month = "December")
Result := "12"
Return, Result
}
Message box shows:
Given: March 7 2009 7:30pm EST 12 hours later: (EST): 8/Mar/2009 07:30h (GMT): 8/Mar/2009 12:30h
[edit] C
Works with: POSIX
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main()
{
struct tm ts;
time_t t;
const char *d = "March 7 2009 7:30pm EST";
strptime(d, "%B %d %Y %I:%M%p %Z", &ts);
/* ts.tm_hour += 12; instead of t += 12*60*60
works too. */
t = mktime(&ts);
t += 12*60*60;
printf("%s", ctime(&t));
return EXIT_SUCCESS;
}
Note: ctime treats the date as local, so that it is like the timezone information were discarded (to see the passage to daylight saving time I must change the date into March 28... no matter the timezone specified)
[edit] C#
class Program
{
static void Main(string[] args)
{
CultureInfo ci=CultureInfo.CreateSpecificCulture("en-US");
string dateString = "March 7 2009 7:30pm EST";
string format = "MMMM d yyyy h:mmtt z";
DateTime myDateTime = DateTime.ParseExact(dateString.Replace("EST","+6"),format,ci) ;
DateTime newDateTime = myDateTime.AddHours(12).AddDays(1) ;
Console.WriteLine(newDateTime.ToString(format).Replace("-5","EST")); //probably not the best way to do this
Console.ReadLine();
}
}
[edit] C++
Library: Boost
compiled with g++ -lboost_date_time
#include <string>
#include <iostream>
#include <boost/date_time/local_time/local_time.hpp>
#include <sstream>
#include <boost/date_time/gregorian/gregorian.hpp>
#include <vector>
#include <boost/algorithm/string.hpp>
#include <cstdlib>
#include <locale>
int main( ) {
std::string datestring ("March 7 2009 7:30pm EST" ) ;
//we must first parse the date string into a date , a time and a time
//zone part , to take account of present restrictions in the input facets
//of the Boost::DateTime library used for this example
std::vector<std::string> elements ;
//parsing the date string
boost::split( elements , datestring , boost::is_any_of( " " ) ) ;
std::string datepart = elements[ 0 ] + " " + "0" + elements[ 1 ] + " " +
elements[ 2 ] ; //we must add 0 to avoid trouble with the boost::date_input format strings
std::string timepart = elements[ 3 ] ;
std::string timezone = elements[ 4 ] ;
const char meridians[ ] = { 'a' , 'p' } ;
//we have to find out if the time is am or pm, to change the hours appropriately
std::string::size_type found = timepart.find_first_of( meridians, 0 ) ;
std::string twelve_hour ( timepart.substr( found , 1 ) ) ;
timepart = timepart.substr( 0 , found ) ; //we chop off am or pm
elements.clear( ) ;
boost::split( elements , timepart , boost::is_any_of ( ":" ) ) ;
long hour = std::atol( (elements.begin( ))->c_str( ) ) ;// hours in the string
if ( twelve_hour == "p" ) //it's post meridian, we're converting to 24-hour-clock
hour += 12 ;
long minute = std::atol( ( elements.begin( ) + 1)->c_str( ) ) ;
boost::local_time::tz_database tz_db ;
tz_db.load_from_file( "/home/ulrich/internetpages/date_time_zonespec.csv" ) ;
//according to the time zone database, this corresponds to one possible EST time zone
boost::local_time::time_zone_ptr dyc = tz_db.time_zone_from_region( "America/New_York" ) ;
//this is the string input format to initialize the date field
boost::gregorian::date_input_facet *f =
new boost::gregorian::date_input_facet( "%B %d %Y" ) ;
std::stringstream ss ;
ss << datepart ;
ss.imbue( std::locale( std::locale::classic( ) , f ) ) ;
boost::gregorian::date d ;
ss >> d ;
boost::posix_time::time_duration td ( hour , minute , 0 ) ;
//that's how we initialize the New York local time , by using date and adding
//time duration with values coming from parsed date input string
boost::local_time::local_date_time lt ( d , td , dyc ,
boost::local_time::local_date_time::NOT_DATE_TIME_ON_ERROR ) ;
std::cout << "local time: " << lt << '\n' ;
ss.str( "" ) ;
ss << lt ;
//we have to add 12 hours, so a new time duration object is created
boost::posix_time::time_duration td2 (12 , 0 , 0 , 0 ) ;
boost::local_time::local_date_time ltlater = lt + td2 ; //local time 12 hours later
boost::gregorian::date_facet *f2 =
new boost::gregorian::date_facet( "%B %d %Y , %R %Z" ) ;
std::cout.imbue( std::locale( std::locale::classic( ) , f2 ) ) ;
std::cout << "12 hours after " << ss.str( ) << " it is " << ltlater << " !\n" ;
//what's New York time in the Berlin time zone ?
boost::local_time::time_zone_ptr bt = tz_db.time_zone_from_region( "Europe/Berlin" ) ;
std::cout.imbue( std::locale( "de_DE.UTF-8" ) ) ; //choose the output forman appropriate for the time zone
std::cout << "This corresponds to " << ltlater.local_time_in( bt ) << " in Berlin!\n" ;
return 0 ;
}
this produces the following output:
local time: 2009-Mar-07 19:30:00 EST 12 hours after 2009-Mar-07 19:30:00 EST it is 2009-Mar-08 08:30:00 EDT ! This corresponds to 2009-Mär-08 13:30:00 CET in Berlin!
[edit] F#
The .NET framework does not support parsing of time zone identifiers like "EST". We have to use time zone offsets like "-5".
open System
let main() =
let est = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time")
let date = DateTime.Parse("March 7 2009 7:30pm -5" )
let date_est = TimeZoneInfo.ConvertTime( date, est)
let date2 = date.AddHours(12.0)
let date2_est = TimeZoneInfo.ConvertTime( date2, est)
Console.WriteLine( "Original date in local time : {0}", date )
Console.WriteLine( "Original date in EST : {0}", date_est )
Console.WriteLine( "12 hours later in local time: {0}", date2 )
Console.WriteLine( "12 hours later in EST : {0}", date2_est )
main()
Output (depends on locale settings):
Original date in local time : 08.03.2009 01:30:00 Original date in EST : 07.03.2009 19:30:00 12 hours later in local time: 08.03.2009 13:30:00 12 hours later in EST : 08.03.2009 07:30:00
[edit] Haskell
import Data.Time.Clock.POSIX
import Data.Time.Format
import System.Locale
main = print t2
where t1 = readTime defaultTimeLocale
"%B %e %Y %l:%M%P %Z"
"March 7 2009 7:30pm EST"
t2 = posixSecondsToUTCTime $ 12*60*60 + utcTimeToPOSIXSeconds t1
[edit] HicEst
CHARACTER date="March 7 2009 7:30pm EST", am_pm, result*20
EDIT(Text=date, Parse=cMonth, GetPosition=next)
month = 1 + EDIT(Text='January,February,March,April,May,June,July,August,September,October,November,December', Right=cMonth, Count=',' )
READ(Text=date(next:)) day, year, hour, minute, am_pm
hour = hour + 12*(am_pm == 'p')
TIME(MOnth=month, Day=day, Year=year, Hour=hour, MInute=minute, TO, Excel=xls_day)
WRITE(Text=result, Format="UWWW CCYY-MM-DD HH:mm") xls_day + 0.5
! result = "Sun 2009-03-08 07:30"
END
[edit] Java
import java.util.Date;
import java.text.SimpleDateFormat;
public class DateManip{
public static void main(String[] args) throws Exception{
String dateStr = "March 7 2009 7:30pm EST";
SimpleDateFormat sdf = new SimpleDateFormat("MMMM d yyyy h:mma zzz");
Date date = sdf.parse(dateStr);
date.setTime(date.getTime() + 43200000l);
System.out.println(sdf.format(date));
}
}
Output:
March 8 2009 8:30AM EDT
or using System.out.println(date); as the last line:
Sun Mar 08 08:30:00 EDT 2009
[edit] Mathematica
dstr = "March 7 2009 7:30pm EST";
DateString[DatePlus[dstr, {12, "Hour"}], {"DayName", " ", "MonthName", " ", "Day", " ", "Year", " ", "Hour24", ":", "Minute", "AMPM"}]
[edit] Perl
We use Mountain Standard Time for output.
use DateTime;
use DateTime::Format::Strptime 'strptime';
strptime('%b %d %Y %I:%M%p %z', 'March 7 2009 7:30pm -0500')->
add(hours => 12)->
set_time_zone('MST')->
strftime('%b %d %Y %I:%M %p MST'),
"\n";
We need to use "-0500" in the input rather than "EST" because DateTime::Format::Strptime rejects the latter as ambiguous— "EST" could refer to the Eastern Time Zone or to Australian Eastern Standard Time.
[edit] PHP
<?php
$time = new DateTime('March 7 2009 7:30pm EST');
$time->modify('+12 hours');
echo $time->format('c');
?>
[edit] PicoLisp
(de timePlus12 (Str)
(use (@Mon @Day @Year @Time @Zone)
(and
(match
'(@Mon " " @Day " " @Year " " @Time " " @Zone)
(chop Str) )
(setq @Mon (index (pack @Mon) *MonFmt))
(setq @Day (format @Day))
(setq @Year (format @Year))
(setq @Time
(case (tail 2 @Time)
(("a" "m") ($tim (head -2 @Time)))
(("p" "m") (+ `(time 12 0) ($tim (head -2 @Time))))
(T ($tim @Time)) ) )
(let? Date (date @Year @Mon @Day)
(when (>= (inc '@Time `(time 12 0)) 86400)
(dec '@Time 86400)
(inc 'Date) )
(pack (dat$ Date "-") " " (tim$ @Time T) " " @Zone) ) ) ) )
[edit] PL/I
/* The PL/I date functions handle dates and time in 49 */
/* different formats, but not that particular one. For any of the */
/* standard formats, the following date manipulation will add */
/* 12 hours to the current date/time. */
seconds = SECS(DATETIME());
seconds = seconds + 12*60*60;
put list (SECSTODATE(secs));
[edit] Python
I don't do anything with timezone here, but it is possible.
import datetime
def mt():
datime1="March 7 2009 7:30pm EST"
formatting = "%B %d %Y %I:%M%p "
datime2 = datime1[:-3] # format can't handle "EST" for some reason
tdelta = datetime.timedelta(hours=12) # twelve hours..
s3 = datetime.datetime.strptime(datime2, formatting)
datime2 = s3+tdelta
print datime2.strftime("%B %d %Y %I:%M%p %Z") + datime1[-3:]
mt()
[edit] R
time <- strptime("March 7 2009 7:30pm EST", "%B %d %Y %I:%M%p %Z") # "2009-03-07 19:30:00"
isotime <- ISOdatetime(1900 + time$year, time$mon, time$mday,
time$hour, time$min, time$sec, "EST") # "2009-02-07 19:30:00 EST"
twelvehourslater <- isotime + 12 * 60 * 60 # "2009-02-08 07:30:00 EST"
timeincentraleurope <- format(isotime, tz="CET", usetz=TRUE) #"2009-02-08 01:30:00 CET"
[edit] REBOL
rebol [
Title: "Date Manipulation"
Author: oofoe
Date: 2009-12-06
URL: http://rosettacode.org/wiki/Date_Manipulation
]
; Only North American zones here -- feel free to extend for your area.
zones: [
NST -3:30 NDT -2:30 AST -4:00 ADT -3:00 EST -5:00 EDT -4:00
CST -6:00 CDT -5:00 MST -7:00 MDT -6:00 PST -8:00 PDT -7:00 AKST -9:00
AKDT -8:00 HAST -10:00 HADT -9:00]
read-time: func [
text
/local m d y t z
][
parse load text [
set m word! (m: index? find system/locale/months to-string m)
set d integer! set y integer!
set t time! set tz word!]
to-date reduce [y m d t zones/:tz]
]
print 12:00 + read-time "March 7 2009 7:30pm EST"
Output:
8-Mar-2009/7:30-5:00
[edit] Ruby
The Time package in the standard library adds a parse method to the core Time class.
Library: RubyGems Library: ActiveSupport
require 'time'
d = "March 7 2009 7:30pm EST"
t = Time.parse(d)
puts t.rfc2822
puts t.zone
new = t + 12*3600
puts new.rfc2822
puts new.zone
# another timezone
require 'rubygems'
require 'active_support'
zone = ActiveSupport::TimeZone['Beijing']
remote = zone.at(new)
# or, remote = new.in_time_zone('Beijing')
puts remote.rfc2822
puts remote.zone
outputs
Sat, 07 Mar 2009 19:30:00 -0500 EST Sun, 08 Mar 2009 08:30:00 -0400 EDT Sun, 08 Mar 2009 20:30:00 +0800 CST
Using ActiveSupport, we can add 12 hours with any of:
new = t + 12.hours
new = t.in(12.hours)
new = t.advance(:hours => 12)
[edit] Smalltalk
Works with: GNU Smalltalk
The aim of the class DateTimeTZ is to provide the ability to understand time with "meridian" (PM/AM, even though no checks are done to assure coherency of the format) and to handle timezones despite the locale (which anyway is gently "ignored", or rather unknown in the format of letters, to Date), providing a proper set of informations to the method readFromWithMeridian:andTimeZone:.
The aDict argument must be a dictionary where keys are the abbreviated timezone code (e.g. EST), and values are three-elements array: difference between the timezone and GMT (as Duration), the DateTime when there's passage between using or not using the daylight saving time (year is ignored), and the "direction" (as Duration) of the change. All data must be filled by hand... As example I've put EST (and there's no way to represent the "new" date and time correctly with the new EDT timezone).
The code also fails when adding a duration that "jumps" beyond two DST changes (e.g from EST to EDT and EST again); (it could be partially fixed by considering intervals instead of single date, and adding a fourth element to link to the "new" timezone abbreviation)
DateTime extend [
setYear: aNum [ year := aNum ]
].
Object subclass: DateTimeTZ [
|dateAndTime timeZoneDST timeZoneName timeZoneVar|
DateTimeTZ class >> new [ ^(super basicNew) ]
DateTimeTZ class >> readFromWithMeridian: aStream andTimeZone: aDict [
|me|
me := self new.
^ me initWithMeridian: aStream andTimeZone: aDict
]
initWithMeridian: aStream andTimeZone: aDict [ |s|
dateAndTime := DateTime readFrom: aStream copy.
s := aStream collection asString.
s =~ '[pP][mM]'
ifMatched: [ :m |
dateAndTime := dateAndTime + (Duration days: 0 hours: 12 minutes: 0 seconds: 0)
].
aDict keysAndValuesDo: [ :k :v |
s =~ k
ifMatched: [ :x |
dateAndTime := dateAndTime setOffset: (v at: 1).
timeZoneDST := (v at: 2) setOffset: (v at: 1).
timeZoneVar := (v at: 3).
timeZoneDST setYear: (self year). "ignore the year"
timeZoneName := k
]
].
^ self
]
setYear: aNum [ dateAndTime setYear: aNum ]
year [ ^ dateAndTime year ]
timeZoneName [ ^timeZoneName ]
+ aDuration [ |n|
n := dateAndTime + aDuration.
(n > timeZoneDST) ifTrue: [ n := n + timeZoneVar ].
^ (self copy dateTime: n)
]
dateTime [ ^dateAndTime ]
dateTime: aDT [ dateAndTime := aDT ]
].
Usage example (note: the code is rather rigid, so not all operations possible on DateTime are possible on DateTimeTZ).
|s abbrDict dt|
s := 'March 7 2009 7:30pm EST'.
"Build a abbreviation -> offset for timezones (example)"
abbrDict := Dictionary new.
abbrDict at: 'EST'
put: { (Duration days: 0 hours: -5 minutes: 0 seconds: 0).
(DateTime year: 2009 month: 3 day: 8 hour: 2 minute: 0 second: 0).
(Duration days: 0 hours: 1 minutes: 0 seconds: 0) }.
dt := DateTimeTZ readFromWithMeridian: (s readStream) andTimeZone: abbrDict.
dt := dt + (Duration days: 0 hours: 12 minutes: 0 seconds: 0).
"let's print it"
('%1 %2 %3 %4:%5%6 %7' %
{
(dt dateTime) monthName asString.
(dt dateTime) day.
(dt dateTime) year.
(dt dateTime) hour12.
(dt dateTime) minute.
(dt dateTime) meridianAbbreviation asString.
dt timeZoneName.
}) displayNl.
(dt dateTime) asUTC displayNl.
Output example (note that EST should be EDT):
March 8 2009 8:30AM EST 2009-03-08T13:30:00+00:00
[edit] Tcl
Works with: Tcl version 8.5
set date "March 7 2009 7:30pm EST"
set epoch [clock scan $date -format "%B %d %Y %I:%M%p %z"]
set later [clock add $epoch 12 hours]
puts [clock format $later] ;# Sun Mar 08 08:30:00 EDT 2009
puts [clock format $later -timezone :Asia/Shanghai] ;# Sun Mar 08 20:30:00 CST 2009
Note the transition into daylight savings time in the interval (in the Eastern timezone).
[edit] UNIX Shell
requires GNU date
date -d 'March 7 2009 7:30pm EST +12 hours'
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