Convert between world time zones with daylight saving times

This is a very simple yet powerful function to convert a datenum from one timezone to another.

Description

As I could find no built-in function nor reliable contribution to achieve that, I had no choice but to write my own, leveraging the GregorianCalendar Java class.
Usage is quite simple:
    targetDST = TimezoneConvert( dn, fromTimezone, toTimezone )

The datenum dn corresponds to the datetime you want to convert. Just specify from which timezone it comes and the target timezone, and you should get the expected result, that takes into account daylight saving time.

Feel free to let me know if I can extend it to support more situations (like Julian Calendar, obviously ;-).

You can get the name of the available timezones using this command:
    TimeZone.getAvailableIDs
after importing the relevant java packages.
    import java.lang.String
    import java.util.* java.awt.*
    import java.util.Enumeration

• MATLAB release: MATLAB 7.4 (R2007a)
• Other requirements: Java

[K E]

Seems to crash because the following mfiles are not included:
year
month
day
hour
minute
second
Or have I misunderstood how to run this?
t1 = TimezoneConvert(now, 'UTC', 'US/Eastern')

[Erwin Mayer]

Hi K E, from what I could see these functions are normally part of the Financial Toolbox. Aren't they enabled by default?

[K E]

OK, that's why - I don't have the Financial Toolbox.
Thanks, KE

[David Goldsmith]

"Feel free to let me know if I can extend it to support more situations"

Well, since K E wasn't explicit: can you make it Financial-Toolbox-free (i.e., not dependent on having that)?

[Justinas]

This function does not seem to adjust historical time for the DST, does it?

[Erwin Mayer]

Hi Justinas, it should adjust historical time for the DST, that was the purpose. At least provided the functions from the Java package support them (probably not for dates very far away) Let me know if it does not work with a special case.

[David]

thank you!

[Yuxiao Qin]

Thank you so much for the file... I was always working on APIs, which cannot display historical DST... Never thought matlab itself can do the job... Much appreciation!

[Matt Aldrich]

What about vectorized support?