> -----Original Message-----
> From: r-help-boun...@r-project.org
> [mailto:r-help-boun...@r-project.org] On Behalf Of peter dalgaard
> Sent: Wednesday, October 06, 2010 7:22 AM
> To: Henrique Dallazuanna
> Cc: r-help@r-project.org; Andre Easom
> Subject: Re: [R] Adding a time variable prior to using reshape
>
>
> On Oct 6, 2010, at 16:11 , Henrique Dallazuanna wrote:
>
> > Try this:
> >
> > with(foo, ave(Value, Label, FUN = seq)) will generate the
> time variable
>
> Make that FUN=seq_along to avoid trouble with groups of size 1.
Sometimes (but not with seq) you also have to worry about
groups of size 0. It seems a waste and sometimes causes
errors for ave() to call FUN for groups of size 0:
> trace(seq_along, quote(cat("length(x)=", length(..1), "\n")))
Tracing function "seq_along" in package "base"
[1] "seq_along"
Warning message:
In .makeTracedFunction(def, tracer, exit, at, print, doEdit) :
making a traced version of a primitive; arguments will be treated as
'...'
> ave(101:110, factor(rep(letters[2:4],c(3,3,4)),
levels=letters[1:6]), FUN=seq_along)
Tracing FUN(X[[1L]], ...) on entry
length(x)= 0
trace: .prim(...)
Tracing FUN(X[[2L]], ...) on entry
length(x)= 3
trace: .prim(...)
Tracing FUN(X[[3L]], ...) on entry
length(x)= 3
trace: .prim(...)
Tracing FUN(X[[4L]], ...) on entry
length(x)= 4
trace: .prim(...)
Tracing FUN(X[[5L]], ...) on entry
length(x)= 0
trace: .prim(...)
Tracing FUN(X[[6L]], ...) on entry
length(x)= 0
trace: .prim(...)
Tracing seq_along(x) on entry
length(x)= 10
trace: .prim(...)
[1] 1 2 3 1 2 3 1 2 3 4
Three calls to seq_along(X[[i]]), for i=c(2,3,4),
would suffice.
Bill Dunlap
Spotfire, TIBCO Software
wdunlap tibco.com
>
>
> --
> Peter Dalgaard
> Center for Statistics, Copenhagen Business School
> Solbjerg Plads 3, 2000 Frederiksberg, Denmark
> Phone: (+45)38153501
> Email: pd....@cbs.dk Priv: pda...@gmail.com
>
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