Date manipulation
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.
Ada
ignoring input timezone for now (it defaults to UTC). feel free to add it.
<lang Ada>with Ada.Calendar.Formatting; with Ada.Strings.Fixed; with Ada.Text_IO; procedure Add_Hours is
use type Ada.Calendar.Time;
Parse_Error : Exception;
function Date_Value (From : String) return Ada.Calendar.Time is
use Ada.Strings.Fixed;
function Month_Value (From : String) return Ada.Calendar.Month_Number is
begin
if From = "January" then return 1;
elsif From = "February" then return 2;
elsif From = "March" then return 3;
elsif From = "April" then return 4;
elsif From = "May" then return 5;
elsif From = "June" then return 6;
elsif From = "July" then return 7;
elsif From = "August" then return 8;
elsif From = "September" then return 9;
elsif From = "October" then return 10;
elsif From = "November" then return 11;
elsif From = "December" then return 12;
else raise Parse_Error;
end if;
end Month_Value;
function Time_Value (From : String) return Ada.Calendar.Day_Duration is
Colon_Index : Positive := Index (From, ":");
Hours : Ada.Calendar.Formatting.Hour_Number := Integer'Value (From (From'First .. Colon_Index - 1));
Minutes : Ada.Calendar.Formatting.Minute_Number := Integer'Value (From (Colon_Index + 1 .. Colon_Index + 2));
begin
if From (From'Last - 1) = 'p' then
Hours := Hours + 12;
end if;
return Ada.Calendar.Formatting.Seconds_Of (Hours, Minutes);
end Time_Value;
Month_End : Natural := Index (From, " ", From'First);
Day_End : Natural := Index (From, " ", Month_End + 1);
Year_End : Natural := Index (From, " ", Day_End + 1);
Time_End : Natural := Index (From, " ", Year_End + 1);
The_Month : Ada.Calendar.Month_Number := Month_Value (From (From'First .. Month_End - 1));
The_Day : Ada.Calendar.Day_Number := Integer'Value (From (Month_End + 1 .. Day_End));
The_Year : Ada.Calendar.Year_Number := Integer'Value (From (Day_End + 1 .. Year_End));
The_Time : Ada.Calendar.Day_Duration := Time_Value (From (Year_End + 1 .. Time_End - 1));
begin
-- ignore time zone (feel free to add)
return Ada.Calendar.Time_Of (The_Year, The_Month, The_Day, The_Time);
end Date_Value;
Given_String : String := "March 7 2009 7:30pm EST"; Offset : Duration := 12 * 60 * 60.0; -- seconds Date : Ada.Calendar.Time := Date_Value (Given_String) + Offset;
begin
Ada.Text_IO.Put_Line (Ada.Calendar.Formatting.Image (Date));
end Add_Hours;</lang>
Output (since input is assumed to be UTC, EST gives wrong time):
$ TZ=UTC ./add_hours 2009-03-08 07:30:00 $ TZ=EST ./add_hours 2009-03-08 12:30:00
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.
<lang AppleScript>set x to "March 7 2009 7:30pm EST"
return (date x) + 12 * hours</lang>
Result is: <lang AppleScript>date "Sunday, March 8, 2009 7:30:00 AM"</lang>
AutoHotkey
<lang 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
}</lang> 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
C
<lang c>#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;
}</lang>
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)
C#
<lang csharp>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(); }
}</lang>
C++
compiled with g++ -lboost_date_time <lang cpp>#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 ;
} </lang> 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!
Clojure
<lang Clojure>(import java.util.Date java.text.SimpleDateFormat)
(defn time+12 [s]
(let [sdf (SimpleDateFormat. "MMMM d yyyy h:mma zzz")] (-> (.parse sdf s)
(.getTime ,) (+ , 43200000) long (Date. ,) (->> , (.format sdf ,)))))</lang>
Delphi
<lang Delphi> program DateManipulation;
{$APPTYPE CONSOLE}
uses
SysUtils, DateUtils;
function MonthNumber(aMonth: string): Word; begin
//Convert a string value representing the month //to its corresponding numerical value if aMonth = 'January' then Result:= 1 else if aMonth = 'February' then Result:= 2 else if aMonth = 'March' then Result:= 3 else if aMonth = 'April' then Result:= 4 else if aMonth = 'May' then Result:= 5 else if aMonth = 'June' then Result:= 6 else if aMonth = 'July' then Result:= 7 else if aMonth = 'August' then Result:= 8 else if aMonth = 'September' then Result:= 9 else if aMonth = 'October' then Result:= 10 else if aMonth = 'November' then Result:= 11 else if aMonth = 'December' then Result:= 12 else Result:= 12;
end;
function ParseString(aDateTime: string): TDateTime; var
strDay, strMonth, strYear, strTime: string; iDay, iMonth, iYear: Word; TimePortion: TDateTime;
begin
//Decode the month from the given string
strMonth:= Copy(aDateTime, 1, Pos(' ', aDateTime) - 1);
Delete(aDateTime, 1, Pos(' ', aDateTime));
iMonth:= MonthNumber(strMonth);
//Decode the day from the given string
strDay:= Copy(aDateTime, 1, Pos(' ', aDateTime) - 1);
Delete(aDateTime, 1, Pos(' ', aDateTime));
iDay:= StrToIntDef(strDay, 30);
//Decode the year from the given string
strYear:= Copy(aDateTime, 1, Pos(' ', aDateTime) -1);
Delete(aDateTime, 1, Pos(' ', aDateTime));
iYear:= StrToIntDef(strYear, 1899);
//Decode the time value from the given string
strTime:= Copy(aDateTime, 1, Pos(' ', aDateTime) -1);
//Encode the date value and assign it to result Result:= EncodeDate(iYear, iMonth, iDay);
//Encode the time value and add it to result if TryStrToTime(strTime, TimePortion) then Result:= Result + TimePortion;
end;
function Add12Hours(aDateTime: string): string; var
tmpDateTime: TDateTime;
begin
//Adding 12 hours to the given //date time string value tmpDateTime:= ParseString(aDateTime); tmpDateTime:= IncHour(tmpDateTime, 12);
//Formatting the output
Result:= FormatDateTime('mm/dd/yyyy hh:mm AM/PM', tmpDateTime);
end;
begin
Writeln(Add12Hours('March 7 2009 7:30pm EST'));
Readln;
end. </lang>
The output of the Delphi program is: "03/08/2009 07:30 AM"
F#
The .NET framework does not support parsing of time zone identifiers like "EST". We have to use time zone offsets like "-5".
<lang fsharp>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()</lang>
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
Fantom
In the expression "d + 12hr", the "12hr" defines an instance of the Duration class, interpreting the duration in nanoseconds.
<lang fantom> fansh> d := DateTime.fromLocale("March 7 2009 7:30pm EST", "MMMM D YYYY h:mmaa zzz") fansh> d 2009-03-07T19:30:00-05:00 EST fansh> d + 12hr 2009-03-08T07:30:00-05:00 EST fansh> (d+12hr).toTimeZone(TimeZone("London")) // the extra credit! 2009-03-08T12:30:00Z London </lang>
Frink
Frink parses a large number of date/time formats, has robust date/time math, and automatically converts between timezones. By default, output times are in the user's defined timezone. <lang frink>
- MMM dd yyyy h:mma ###
d = parseDate["March 7 2009 7:30pm EST"] println[d + 12 hours -> Eastern] println[d + 12 hours -> Switzerland] // Extra credit </lang>
Output is:
AD 2009-03-08 AM 08:30:00.000 (Sun) Eastern Daylight Time AD 2009-03-08 PM 01:30:00.000 (Sun) Central European Time
Go
Library parser uses an easy-to-read prototype. Library formatter offers only two choices for time zone, local and UTC. Otherwise the library formatter has lots of flexibility, but code here just takes the default, "UnixDate" format. <lang go>package main
import (
"fmt" "time"
)
const taskDate = "March 7 2009 7:30pm EST" const taskFormat = "January 2 2006 3:04pm MST"
func main() {
fmt.Println("Input:", taskDate)
t, err := time.Parse(taskFormat, taskDate)
if err != nil {
fmt.Println(err)
return
}
t2 := t.Seconds() + 12*60*60
fmt.Println("+12 hrs, local:", time.SecondsToLocalTime(t2))
fmt.Println("+12 hrs, UTC: ", time.SecondsToUTC(t2))
}</lang> Output:
Input: March 7 2009 7:30pm EST +12 hrs, local: Sun Mar 8 08:30:00 EDT 2009 +12 hrs, UTC: Sun Mar 8 12:30:00 UTC 2009
Haskell
<lang 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</lang>
HicEst
<lang 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
</lang>
Icon and Unicon
This uses the datetime procedures from the Icon Programming Library. Several supplemental procedures were needed to normalize the date format (as the one used in the task isn't fully compatible with the library), and to better handle time zones (as the library routines don't handle part hour time zones).
<lang Icon>link datetime
procedure main() write("input = ",s := "March 7 2009 7:30pm EST" ) write("+12 hours = ",SecToTZDateLine(s := TZDateLineToSec(s) + 12*3600,"EST")) write(" = ",SecToTZDateLine(s,"UTC")) write(" = ",SecToTZDateLine(s,"NST")) end
procedure SecToTZDateLine(s,tz) #: returns dateline + time zone given seconds return NormalizedDate(SecToDateLine(s+\(_TZdata("table")[\tz|"UTC"]))||" "|| tz) end
procedure TZDateLineToSec(s) #: returns seconds given dateline (and time zone)
return (
NormalizedDate(s) ? (
d := tab(find("am"|"pm")+2),tab(many('\t ,')),
tz := \_TZdata("table")[tab(0)]
),
DateLineToSec(d) - tz)
end
procedure NormalizedDate(s) #: returns a consistent dateline static D,M initial {
D := ["Saturday","Sunday","Monday","Tuesday","Wednesday","Thursday","Friday"]
M := ["January","February","March","April","May","June",
"July","August","September","October","November","December"]
}
map(s) ? { # parse and build consistent dateline
ds := 1(x := !D, =map(x)) | "" # Weekday
ds ||:= 1(", ", tab(many('\t ,')|&pos))
ds ||:= 1(x := !M, =map(x)) | fail # Month
ds ||:= 1(" ", tab(many('\t ,')|&pos))
ds ||:= tab(many(&digits)) | fail # day
ds ||:= 1(", ", tab(many('\t ,'))) | fail
ds ||:= tab(many(&digits)) | fail # year
ds ||:= 1(" ", tab(many('\t ,'))) | fail
ds ||:= tab(many(&digits))||(=":"||tab(many(&digits))|&null) | fail # time
ds ||:= 1(" ", tab(many('\t ,')|&pos))
ds ||:= =("am"|"pm") | fail # halfday
ds ||:= 1(" ", tab(many('\t ,')|&pos))
tz := map(=!_TZdata("list"),&lcase,&ucase)
}
if ds[1] == "," then
ds := SecToDateLine(DateLineToSec("Sunday"||ds)) # get IPL to fix weekday
return ds ||:= " " || \tz|"UTC" end
procedure _TZdata(x) #: internal return TZ data (demo version incomplete) static TZ,AZ initial {
TZ := table()
AZ := []
"UTC/0;ACDT/+10.5;CET/1;EST/-5;NPT/+5.75;NST/-3.5;PST/-8;" ?
while ( a := tab(find("/")), move(1), o := tab(find(";")), move(1) ) do {
TZ[map(a)] := TZ[a] := integer(3600*o)
put(AZ,a,map(a))
}
every TZ[&null|""] := TZ["UTC"]
}
return case x of { "list" : AZ ; "table" : TZ } end</lang>
datetime provides SecToDateLine, and DateLineToSec these convert between Icon's &dateline format and seconds from a configurable base date (which defaults to the normal 1970 epoch).
Output:
input = March 7 2009 7:30pm EST
+12 hours = Sunday, March 8, 2009 7:30 am EST
= Sunday, March 8, 2009 12:30 pm UTC
= Sunday, March 8, 2009 9:00 am NST
Java
<lang 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));
}
}</lang> 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
JavaScript
Input: March 7 2009 7:30pm EST
The input string is ambiguous since EST might represent any one of 3 different world time zones. Will assume US Eastern Standard Time of UTC -5 hours.
Javascript date objects are always in the local time zone. If a date and time is provided in a different time zone, it must be dealt with manually as the date object's time zone offset is read only. Consequently, there may be issues if daylight saving is observed in one location but not the other.
While ECMA-262 Ed 5 specifies a Date.parse method, it is not widely supported (2011) and parsing of strings other than the format specified are implementation dependent. Since the test string doesn't conform to the standard, it must be manually parsed.
<lang JavaScript>function add12hours(dateString) {
// Get the parts of the date string
var parts = dateString.split(/\s+/);
var date = parts[1];
var month = parts[0];
var year = parts[2];
var time = parts[3];
var ampm = time && time.match(/[a-z]+$/i)[0];
var hr = Number(time.split(':')[0]);
var min = Number(time.split(':')[1].replace(/\D/g,));
var zone = parts[4].toUpperCase();
var months = ['January','February','March','April','May','June',
'July','August','September','October','November','December'];
var zones = {'EST': 300, 'AEST': -600}; // Minutes to add to zone time to get UTC
// Convert month name to number, zero indexed
// Could use indexOf but not supported widely
for (var i=0, iLen=months.length; i<iLen; i++) {
if (months[i] == month) {
month = i;
}
}
if (typeof month != 'number') return; // Invalid month name provided
// Convert hours to 24hr
if (ampm && ampm.toLowerCase() == 'pm') {
hr += 12;
}
// Add 12 hours to hours hr += 12;
// Create a date object in local zone var d = new Date(year, month, date); d.setHours(hr, min, 0, 0);
// Adjust minutes for the time zones d.setMinutes(d.getMinutes() + zones[zone] - d.getTimezoneOffset() );
// d is now a local date representing the same moment as the // source date plus 12 hours return d;
}
var inputDateString = 'March 7 2009 7:30pm EST';
alert(
'Input: ' + inputDateString + '\n' + '+12hrs in local time: ' + add12hours(inputDateString) );</lang>
Lua
The following solution is quite ugly, but unfortunately there is not anything like 'strptime'-function in Lua. <lang lua> str = string.lower( "March 7 2009 7:30pm EST" )
month = string.match( str, "%a+" ) if month == "january" then month = 1 elseif month == "february" then month = 2 elseif month == "march" then month = 3 elseif month == "april" then month = 4 elseif month == "may" then month = 5 elseif month == "june" then month = 6 elseif month == "july" then month = 7 elseif month == "august" then month = 8 elseif month == "september" then month = 9 elseif month == "october" then month = 10 elseif month == "november" then month = 11 elseif month == "december" then month = 12 end
strproc = string.gmatch( str, "%d+" ) day = strproc() year = strproc() hour = strproc() min = strproc()
if string.find( str, "pm" ) then hour = hour + 12 end
print( os.date( "%c", os.time{ year=year, month=month, day=day, hour=hour, min=min, sec=0 } + 12 * 3600 ) ) </lang> Output:
Sun Mar 8 07:30:00 2009
Mathematica
<lang Mathematica>dstr = "March 7 2009 7:30pm EST"; DateString[DatePlus[dstr, {12, "Hour"}], {"DayName", " ", "MonthName", " ", "Day", " ", "Year", " ", "Hour24", ":", "Minute", "AMPM"}]</lang>
Pascal
See Delphi
Perl
We use Mountain Daylight Time for output.
<lang perl>use DateTime; use DateTime::Format::Strptime 'strptime'; use feature 'say';
my $input = 'March 7 2009 7:30pm EST'; $input =~ s{EST}{America/New_York};
say strptime('%b %d %Y %I:%M%p %O', $input)
->add(hours => 12)
->set_time_zone('America/Edmonton')
->format_cldr('MMMM d yyyy h:mma zzz');</lang>
If we're given an ambiguous timezone like 'EST' for input, we can handle this by changing it to the unambiguous Olson timezone id. This ensures daylight savings is correctly handled (which is especially tricky here, since March 7/8 is the DST rollover, and times jump ahead skipping an hour)
Output:
March 8 2009 6:30AM MDT
PHP
<lang php><?php $time = new DateTime('March 7 2009 7:30pm EST'); $time->modify('+12 hours'); echo $time->format('c'); ?></lang>
PicoLisp
<lang PicoLisp>(de timePlus12 (Str)
(use (@Mon @Day @Year @Time @Zone)
(and
(match
'(@Mon " " @Day " " @Year " " @Time " " @Zone)
(chop Str) )
(setq @Mon (index (pack @Mon) *MonFmt))
(setq @Day (format @Day))
(setq @Year (format @Year))
(setq @Time
(case (tail 2 @Time)
(("a" "m") ($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) ) ) ) )</lang>
Pike
<lang Pike>> (Calendar.dwim_time("March 7 2009 7:30pm EST")+Calendar.Hour()*12)->set_timezone("CET")->format_ext_time(); Result: "Saturday, 7 March 2009 12:30:00"</lang>
PL/I
<lang 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)); </lang>
Python
I don't do anything with timezone here, but it is possible.
<lang python>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()</lang>
R
<lang 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"</lang>
REBOL
<lang 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" </lang>
Output:
8-Mar-2009/7:30-5:00
REXX
This example is written using the Open Object Rexx dialect to take advantage of the DateTime built–in class.
<lang REXX>/* Rexx */
Do
sampleDate = 'March 7 2009 7:30pm EST'
Parse value sampleDate with tm td ty tt tz .
Parse value time('l', tt, 'c') with hh ':' mm ':' ss '.' us .
timezones. = Call initTimezones mn = monthNameToNumber(tm) zuluOffset = getTZOffset(tz)
Drop !TZ !MSG
day.1.!TZ = zuluOffset
day.1.!MSG = 'Original date:'
day.1 = .DateTime~new(ty, mn, td, hh, mm, ss, us, day.1.!TZ * 60)
day.2.!TZ = zuluOffset
day.2.!MSG = 'Result after adding 12 hours to date:'
day.2 = day.1~addHours(12)
day.3.!TZ = getTZOffset('UTC') -- AKA GMT == Greenwich Mean Time
day.3.!MSG = 'Result shifted to "UTC (Zulu)" time zone:'
day.3 = day.1~toTimeZone(day.3.!TZ)
day.4.!TZ = getTZOffset('PST') -- Pacific Standard Time
day.4.!MSG = 'Result shifted to "Pacific Standard Time" time zone:'
day.4 = day.2~toTimeZone(day.4.!TZ * 60)
day.5.!TZ = getTZOffset('NPT') -- Nepal Time
day.5.!MSG = 'Result shifted to "Nepal Time" time zone:'
day.5 = day.2~toTimeZone(day.5.!TZ * 60)
day.0 = 5
Say 'Manipulate the date string "'sampleDate'" and present results in ISO 8601 timestamp format:' Say Loop d_ = 1 to day.0 Say day.d_.!MSG Say day.d_~isoDate || getUTCOffset(day.d_.!TZ, 'z') Say End d_
Return 0
End Exit
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ isTrue: Procedure; Return (1 == 1)
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ isFalse: Procedure; Return \isTrue()
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ monthNameToNumber: Procedure Do
Parse arg tm .
mnamesList = 'January February March April May June July August September October November December'
Loop mn = 1 to mnamesList~words
mnx = mnamesList~word(mn)
If mnx~upper~abbrev(tm~upper, 3) then Do
Leave mn
End
End mn
Return mn
End Exit
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ getTZOffset: Procedure expose timezones. Do
Parse upper arg tz . Drop !REGION !FULLNAME !OFFSET !ZNAMEALT
offset = 0
Loop z_ = 1 to timezones.0
If tz = timezones.z_ then Do
offset = timezones.z_.!OFFSET
Leave z_
End
End z_
Return offset;
End Exit
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ getUTCOffset: Procedure expose timezones. Do
Parse arg oh ., zulu .
oha = abs(oh)
If oha = 0 & 'ZULU'~abbrev(zulu~upper, 1) then Do
offset = 'Z'
End
else Do
If oh < 0 then ew = '-'
else ew = '+'
om = oha * 60
oom = om // 60 % 1
ooh = om % 60
offset = ew || ooh~right(2, 0) || oom~right(2, 0)
End
Return offset
End Exit
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ initTimezones: Procedure expose timezones. Do
-- Read time zone info from formatted comment block below Drop !REGION !FULLNAME !OFFSET !ZNAMEALT timezones.0 = 0 region = !datBegin = '__DATA__' !datEnd = '__ENDD__' !reading = isFalse()
Loop l_ = 1 to sourceline()
Parse value sourceline(l_) with sl 0 hd +8 .
If !reading then Do
If hd = !datEnd then Do
!reading = isFalse()
Leave l_
End
else Do
Parse value sl with sl '--' .
If sl~strip~length = 0 then Iterate l_
Parse value sl with,
0 '{' zRegion '}',
0 zAbbrev . '!' zFullName '!' zAbbrevOther . '!' zUOffset .
If zRegion~length \= 0 then Do
region = zRegion
Iterate l_
End
else Do
z_ = timezones.0 + 1
timezones.0 = z_
timezones.z_ = zAbbrev~strip~upper
timezones.z_.!FULLNAME = zFullName~strip
timezones.z_.!OFFSET = zUOffset~format
timezones.z_.!ZNAMEALT = zAbbrevOther~strip~upper
timezones.z_.!REGION = region
End
End
End
else Do
If hd = !datBegin then Do
!reading = isTrue()
End
Iterate l_
End
End l_
Return timezones.0
End Exit /*
A "HERE" document, sort of... Everything between the __DATA__ and __ENDD__ delimiters will be read into the timezones. stem:
__DATA__ {Universal} UTC ! Coordinated Universal Time ! ! 0
{Europe} BST ! British Summer Time ! ! +1 CEST ! Central European Summer Time ! ! +2 CET ! Central European Time ! ! +1 EEST ! Eastern European Summer Time ! ! +3 EET ! Eastern European Time ! ! +2 GMT ! Greenwich Mean Time ! ! 0 IST ! Irish Standard Time ! ! +1 KUYT ! Kuybyshev Time ! ! +4 MSD ! Moscow Daylight Time ! ! +4 MSK ! Moscow Standard Time ! ! +3 SAMT ! Samara Time ! ! +4 WEST ! Western European Summer Time ! ! +1 WET ! Western European Time ! ! 0
{North America} ADT ! Atlantic Daylight Time ! HAA ! -3 AKDT ! Alaska Daylight Time ! HAY ! -8 AKST ! Alaska Standard Time ! HNY ! -9 AST ! Atlantic Standard Time ! HNA ! -4 CDT ! Central Daylight Time ! HAC ! -5 CST ! Central Standard Time ! HNC ! -6 EDT ! Eastern Daylight Time ! HAE ! -4 EGST ! Eastern Greenland Summer Time ! ! 0 EGT ! East Greenland Time ! ! -1 EST ! Eastern Standard Time ! HNE,ET ! -5 HADT ! Hawaii-Aleutian Daylight Time ! ! -9 HAST ! Hawaii-Aleutian Standard Time ! ! -10 MDT ! Mountain Daylight Time ! HAR ! -6 MST ! Mountain Standard Time ! HNR ! -7 NDT ! Newfoundland Daylight Time ! HAT ! -2.5 NST ! Newfoundland Standard Time ! HNT ! -3.5 PDT ! Pacific Daylight Time ! HAP ! -7 PMDT ! Pierre & Miquelon Daylight Time ! ! -2 PMST ! Pierre & Miquelon Standard Time ! ! -3 PST ! Pacific Standard Time ! HNP,PT ! -8 WGST ! Western Greenland Summer Time ! ! -2 WGT ! West Greenland Time ! ! -3
{India and Indian Ocean} IST ! India Standard Time ! ! +5.5 PKT ! Pakistan Standard Time ! ! +5 BST ! Bangladesh Standard Time ! ! +6 -- Note: collision with British Summer Time NPT ! Nepal Time ! ! +5.75 BTT ! Bhutan Time ! ! +6 BIOT ! British Indian Ocean Territory Time ! IOT ! +6 MVT ! Maldives Time ! ! +5 CCT ! Cocos Islands Time ! ! +6.5 TFT ! French Southern and Antarctic Time ! ! +5
__ENDD__
- /
</lang>
- Output
Manipulate the date string "March 7 2009 7:30pm EST" and present results in ISO 8601 timestamp format: Original date: 2009-03-07T19:30:00.000000-0500 Result after adding 12 hours to date: 2009-03-08T07:30:00.000000-0500 Result shifted to "UTC (Zulu)" time zone: 2009-03-08T00:30:00.000000Z Result shifted to "Pacific Standard Time" time zone: 2009-03-08T04:30:00.000000-0800 Result shifted to "Nepal Time" time zone: 2009-03-08T18:15:00.000000+0545
Ruby
The Time package in the standard library adds a parse method to the core Time class.
<lang ruby>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</lang> 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: <lang ruby>new = t + 12.hours new = t.in(12.hours) new = t.advance(:hours => 12)</lang>
Scala
<lang scala>import java.text.SimpleDateFormat import java.util.{Calendar, Locale, TimeZone}
object DateManipulation {
def main(args: Array[String]): Unit = {
val input="March 7 2009 7:30pm EST"
val df=new SimpleDateFormat("MMMM d yyyy h:mma z", Locale.ENGLISH)
val c=Calendar.getInstance()
c.setTime(df.parse(input))
c.add(Calendar.HOUR_OF_DAY, 12) println(df.format(c.getTime))
df.setTimeZone(TimeZone.getTimeZone("GMT"))
println(df.format(c.getTime))
}
}</lang>
Output:
March 8 2009 8:30AM EDT March 8 2009 12:30PM GMT
Seed7
Time zone identifiers like "EST" are ambiguous. E.g.: "AST" is used to abbreviate both Atlantic Standard Time (UTC-04) and Arab Standard Time (UTC+03). Therefore parsing of such time zone identifiers is not supported by Seed7. ISO 8601 defines no time zone designators. Instead ISO 8601 specifies time offsets from UTC. In the example below EST is replaced with UTC-05.
<lang seed7>$ include "seed7_05.s7i";
include "time.s7i"; include "duration.s7i";
const func time: parseDate (in string: dateStri) is func
result
var time: result is time.value;
local
const array string: monthNames is [] ("January", "February", "March", "April",
"May", "June", "July", "August", "September", "October", "November", "December");
var array string: dateParts is 0 times "";
var integer: month is 0;
var string: timeStri is "";
begin
dateParts := split(dateStri, ' ');
result.year := integer parse (dateParts[3]);
result.month := 1;
while monthNames[result.month] <> dateParts[1] do
incr(result.month);
end while;
result.day := integer parse (dateParts[2]);
timeStri := dateParts[4];
if endsWith(timeStri, "am") then
result.hour := integer parse (timeStri[.. pred(pos(timeStri, ':'))]);
elsif endsWith(timeStri, "pm") then
result.hour := integer parse (timeStri[.. pred(pos(timeStri, ':'))]) + 12;
else
raise RANGE_ERROR;
end if;
result.minute := integer parse (timeStri[succ(pos(timeStri, ':')) .. length(timeStri) - 2]);
if dateParts[5] <> "UTC" then
result.timeZone := 60 * integer parse (dateParts[5][4 ..]);
end if;
end func;
const proc: main is func
local
var time: aTime is time.value;
begin
aTime := parseDate("March 7 2009 7:30pm UTC-05");
writeln("Given: " <& aTime);
aTime +:= 1 . DAYS;
writeln("A day later: " <& aTime);
aTime := toUTC(aTime);
writeln("In UTC: " <& aTime);
end func;</lang>
Output:
Given: 2009-03-07 19:30:00 UTC-5 A day later: 2009-03-08 19:30:00 UTC-5 In UTC: 2009-03-09 00:30:00 UTC
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)
<lang smalltalk>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 ]
].</lang>
Usage example (note: the code is rather rigid, so not all operations possible on DateTime are possible on DateTimeTZ).
<lang smalltalk>|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.</lang>
Output example (note that EST should be EDT):
March 8 2009 8:30AM EST 2009-03-08T13:30:00+00:00
Tcl
<lang tcl>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</lang>
Note the transition into daylight savings time in the interval (in the Eastern timezone).
UNIX Shell
requires GNU date <lang bash>date -d 'March 7 2009 7:30pm EST +12 hours'</lang>
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