[Rd] length of POSIXlt object (PR#13482)

[Jeff Ryan]

Read the docs. POSIXlt is a list of 9 elements. Each element length is
what you think it should be returning.  That is not correct.

?POSIXlt

Details:

     There are two basic classes of date/times.  Class '"POSIXct"'
     represents the (signed) number of seconds since the beginning of
     1970 as a numeric vector.  Class '"POSIXlt"' is a named list of
     vectors representing

> unclass(as.POSIXlt(as.POSIXlt('2007-01-01')+1:11))
$sec
 [1]  1  2  3  4  5  6  7  8  9 10 11

$min
 [1] 0 0 0 0 0 0 0 0 0 0 0

$hour
 [1] 0 0 0 0 0 0 0 0 0 0 0

$mday
 [1] 1 1 1 1 1 1 1 1 1 1 1

$mon
 [1] 0 0 0 0 0 0 0 0 0 0 0

$year
 [1] 107 107 107 107 107 107 107 107 107 107 107

$wday
 [1] 1 1 1 1 1 1 1 1 1 1 1

$yday
 [1] 0 0 0 0 0 0 0 0 0 0 0

$isdst
 [1] 0 0 0 0 0 0 0 0 0 0 0

attr(,"tzone")
[1] ""    "CST" "CDT"


Jeff


On Wed, Jan 28, 2009 at 4:15 PM,  <twoutopias at gmail.com> wrote:
> The length() of a POSIXlt object is given as 9 regardless of the actual
> length. For example:
>
>> make.date.time
> function (year=c(2006,2006),month=c(8,8),day=2:5,hour=13,minute=45)
> {# convert year, etc., into POSIXlt object
> #
> d=as.character(make.date(year,month,day))
> t=paste(hour,minute,sep=":")
> as.POSIXlt(paste(d,t))
> }
>> t=make.date.time()
>> t
> [1] "2006-08-02 13:45:00" "2006-08-03 13:45:00" "2006-08-04 13:45:00"
> [4] "2006-08-05 13:45:00"
>> length(t)
> [1] 9
>> t[1]
> [1] "2006-08-02 13:45:00"
>> length(t[1])
> [1] 9
>
>
>
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-- 
Jeffrey Ryan
jeffrey.ryan at insightalgo.com

ia: insight algorithmics
www.insightalgo.com