Bug 16733 - as.POSIXlt sets isdst field incorrectly at the end of daylight saving time
Summary: as.POSIXlt sets isdst field incorrectly at the end of daylight saving time
Status: UNCONFIRMED
Alias: None
Product: R
Classification: Unclassified
Component: Accuracy (show other bugs)
Version: R 3.2.2
Hardware: ix86 (32-bit) Windows 32-bit
: P5 minor
Assignee: R-core
URL:
Depends on:
Blocks:
 
Reported: 2016-02-28 01:28 UTC by Geoff Pritchard
Modified: 2016-02-28 01:29 UTC (History)
1 user (show)

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Description Geoff Pritchard 2016-02-28 01:28:43 UTC
With the OS time zone set to New Zealand time, the command

as.POSIXlt("2015-04-05 02:30")$isdst

evaluates to 0, indicating that daylight savings time is not in effect at 02:30 on 5 April 2015.

It ought to yield a negative value, signifying "unknown". There were two 02:30s on 5 April 2015 in New Zealand: one in daylight time, and another 60 minutes later in standard time. The string "2015-04-05 02:30" leaves it unclear which one is being referenced.