[R] Problem using plot and converted dates

[Gabor Grothendieck]

Try:

axis.Date(1, sam5, sam5, format = "%b-%y")

On 4/17/06, s.e.roberts at qmul.ac.uk <s.e.roberts at qmul.ac.uk> wrote:
> Dear R-help,
> My apologies, my previous script ran successfully before I posted as I had
> already created mkf
> as an object in my active workspace. I have had some success, however I am
> unable to plot
> all 9 of the 'sam5' dates using axis.Date:
>
> mkf<-c(0.021375,0.078780,0.028560,0.070278,0.021375,0.078780,0.028560,0.078780,0.021375)
> sam4<-c("03/03/01","03/05/01","03/07/01","03/09/01","03/11/01","04/01/01","04/03/01","04/05/01","04/07/01")
> sam5<-as.Date(sam4,format="%y/%m/%d")
> plot(sam5,mkf,type="l", xaxt="n")
> axis.Date(1, sam5, format = "%b-%y")
>
> # The above just plots 'Jan-04', removing the last 2 gives:
> mkf<-c(0.021375,0.078780,0.028560,0.070278,0.021375,0.078780,0.028560)
> sam4<-c("03/03/01","03/05/01","03/07/01","03/09/01","03/11/01","04/01/01","04/03/01")
> sam5<-as.Date(sam4,format="%y/%m/%d")
> plot(sam5,mkf,type="l", xaxt="n")
> axis.Date(1, sam5, format = "%b-%y")
>
> #I have tried reducing the size using cex.axis (to no avail):
> mkf<-c(0.021375,0.078780,0.028560,0.070278,0.021375,0.078780,0.028560,0.078780,0.021375)
> sam4<-c("03/03/01","03/05/01","03/07/01","03/09/01","03/11/01","04/01/01","04/03/01","04/05/01","04/07/01")
> sam5<-as.Date(sam4,format="%y/%m/%d")
> plot(sam5,mkf,type="l", xaxt="n")
> axis.Date(1, sam5, format = "%b-%y",cex.axis=0.1)
>
>
> #and reducing the margins (also to no avail...):
> mar=c(1,1,1,1)
> mkf<-c(0.021375,0.078780,0.028560,0.070278,0.021375,0.078780,0.028560,0.078780,0.021375)
> sam4<-c("03/03/01","03/05/01","03/07/01","03/09/01","03/11/01","04/01/01","04/03/01","04/05/01","04/07/01")
> sam5<-as.Date(sam4,format="%y/%m/%d")
> plot(sam5,mkf,type="l", xaxt="n")
> axis.Date(1, sam5, format = "%b-%y")
>
>
> Any help gratefully received.
>
> Best wishes,
> Sion
>
> R 2.1.1
>
>
>
> Quoting Prof Brian Ripley <ripley at stats.ox.ac.uk>:
>
> > On Mon, 17 Apr 2006, s.e.roberts at qmul.ac.uk wrote:
> >
> > Please do follow the posting guide and at least tell us your version of R
> > and give a working example (mkf is missing)
> >
> > > Dear R-help,
> > > I am having problems with plotting converted dates in chronological as
> > Mar-03,
> > > May-03...Jul-04.
> > > My script is:
> > >
> > >
> >
> sam4<-c("03/03/01","03/05/01","03/07/01","03/09/01","03/11/01","04/01/01","04/03/01","04/05/01","04/07/01")
> > > sam5<-strptime(sam4,format="%y/%m/%d")
> >
> > I would suggest you use as.Date here, for you have dates, not date-times.
> >
> > > f<-data.frame(sam5,mkf)
> > > plot(f,type="l")
> > > # This works ok, but none of the labels appear on the x-axis,
> >
> > It works for me: it is not intended to plot your labels (and plot.default
> > does not do that either).  If you want add a special axis, use axis.Date
> > to do so.
> >
> > > so I thought I
> > > would convert them using
> > > # as.POSIXct:
> >
> > You have converted them to a factor, which is not what you want.
> >
> > > sam6<-format(as.POSIXct(sam5), "%b-%y")
> > > mon<-factor(as.character(sam6),levels=sam6)
> > > f2<-data.frame(mon,mkf)
> > > plot(f2,type="l")
> > >
> > > The problem is that plot(f2,type="l") no longer produces a line plot...
> >
> > Why don't you use plot(sam5, mkf, type="l")?  That works, and in fact
> > your example works in R 2.3.0RC, but creating a data frame you don't need
> > is counter-productive.
> >
> > --
> > Brian D. Ripley,                  ripley at stats.ox.ac.uk
> > Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> > University of Oxford,             Tel:  +44 1865 272861 (self)
> > 1 South Parks Road,                     +44 1865 272866 (PA)
> > Oxford OX1 3TG, UK                Fax:  +44 1865 272595
> >
>
>
> --
> Siôn Roberts
>
> Department of Geography,
> Queen Mary, University of London,
> London,
> E1 4NS.
>
> Tel: +44 20 7882 5400
> http://www.geog.qmul.ac.uk/postgraduate/student/roberts.html
>
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