R help - Sep 2011 - Problem with zoo::window()

I have the following time series:

 > class(CCasadesz2)
[1] "zoo"
 > setmanes <- cut(time(CCasadesz2),breaks="weeks")
 > CCasadeswz <- aggregate(CCasadesz2,sum,by=setmanes)
 > class(CCasadeswz)
[1] "zoo"
 > summary(CCasadeswz)
                  Index      CCasadeswz
  2009-01-12 00:00:00: 1   Min.   :   4.0
  2009-01-19 00:00:00: 1   1st Qu.: 150.0
  2009-01-26 00:00:00: 1   Median : 268.0
  2009-02-02 00:00:00: 1   Mean   : 316.6
  2009-02-09 00:00:00: 1   3rd Qu.: 387.5
  2009-02-23 00:00:00: 1   Max.   :1435.0
  (Other)            :93

 > summary(time(CCasadeswz))
shows dates for 2009 and 2010, and

 > plot(CCasadeswz)
correctly displays the data for 2009 and 2010.

But when I try to select year 2010:

 > CCasadeswz2010 = window(CCasadeswz,start=as.Date("2010-01-01"), 
end=as.Date("2010-12-31"))
Warning messages:
1: In which(in.index & all.indexes >= start & all.indexes <= end)
:
   Incompatible methods ("Ops.factor", "Ops.Date") for
">="
2: In which(in.index & all.indexes >= start & all.indexes <= end)
:
   Incompatible methods ("Ops.factor", "Ops.Date") for
"<="

 > summary(CCasadeswz2010)
                  Index
  2009-01-12 00:00:00:0
  2009-01-19 00:00:00:0
  2009-01-26 00:00:00:0
  2009-02-02 00:00:00:0
  2009-02-09 00:00:00:0
  2009-02-16 00:00:00:0
  (Other)            :0

(it seems no data have been selected!)

 > plot(CCasadeswz2010)
Error in plot.window(xlim = xlim, ylim = ylim, log = log, yaxs = 
pars$yaxs) :
   need finite 'ylim' values
Calls: plot ... boxplot -> boxplot.default -> do.call -> bxp ->
plot.window
In addition: Warning messages:
1: In min(x) : no non-missing arguments to min; returning Inf
2: In max(x) : no non-missing arguments to max; returning -Inf
3: In min(x) : no non-missing arguments to min; returning Inf
4: In max(x) : no non-missing arguments to max; returning -Inf
5: In is.na(rows) : is.na() applied to non-(list or vector) of type
'NULL'
Error in plot.window(xlim = xlim, ylim = ylim, log = log, yaxs = 
pars$yaxs) :
   need finite 'ylim' values
Calls: plot ... boxplot -> boxplot.default -> do.call -> bxp ->
plot.window

why do I get the warning in window()? My command follows what is 
mentioned in the manual:
R> window(z, start = as.Date("2005-02-15"), end =
as.Date("2005-02-28"))

Thanks
Agus
-- 
Dr. Agustin Lobo
Institut de Ciencies de la Terra "Jaume Almera" (CSIC)
Lluis Sole Sabaris S/N
08028 Barcelona
Spain
Tel. +34 934095410
Fax. +34 934110012
email: Agustin.Lobo at ictja.csic.es

On Tue, Sep 27, 2011 at 5:23 AM, Agustin Lobo
<Agustin.Lobo at ictja.csic.es> wrote:
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
Provide the output of dput(CCasadesz2) or if that is very large try to
cut it down to make the example minimal.

-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

On Tue, Sep 27, 2011 at 5:23 AM, Agustin Lobo
<Agustin.Lobo at ictja.csic.es> wrote:
> I have the following time series:
>
>> class(CCasadesz2)
> [1] "zoo"
>> setmanes <- cut(time(CCasadesz2),breaks="weeks")
>> CCasadeswz <- aggregate(CCasadesz2,sum,by=setmanes)
cut produces a "factor", not a "Date". The by= argument in
aggregate.zoo should not be a factor but rather should define the new
index. If you want the new index to be a "Date" class then by= should
define a "Date" vector.  See ?aggregate.zoo .

Try:

setmanes <- as.Date(format(setmanes))

-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com