Time Zone and Conversion

Temporal objects in DolphinDB do not include time zone information. It is up to users to interpret the time zones of the temporal objects.

DolphinDB automatically detects the local time zones.

We can use the following functions to convert time between different time zones:

(1) localtime convert time from GMT (Greenwich Mean Time) to local time zone.

(2) gmtime convert time from local time zone to GMT (Greenwich Mean Time).

(3) convertTZ convert time between different time zones.

Time zone conversion functions address the daylight saving time automatically if either the source time zone or the destination time zone adopts the daylight saving time.

Examples

The following examples were conducted in US Eastern time zone.

$ localtime(2018.01.22T15:20:26);
2018.01.22T10:20:26

$ localtime(2017.12.16T18:30:10.001);
2017.12.16T13:30:10.001

$ gmtime(2018.01.22 10:20:26);
2018.01.22T15:20:26

$ gmtime(2017.12.16T13:30:10.008);
2017.12.16T18:30:10.008

$ convertTZ(2016.04.25T08:25:45,"US/Eastern","Asia/Shanghai");
2016.04.25T20:25:45


// with daylight saving time in US:
$ convertTZ(2016.04.25T19:25:45,"US/Eastern","Asia/Shanghai");
2016.04.26T07:25:45