[R] plotting dates in x axis

Jim Lemon
Mon, 27 Feb 2017 21:11:05 -0000

Hi Maria,
First, Excel files don't make it through the Mexican Wall. A CSV with
the extension changed to .txt might. You can get all of the years like
this:

aa<-data.frame(var1=runif(180),
 SDATE=paste(sample(1998:2012,180,TRUE),
 sample(1:12,180,TRUE),sample(1:28,180,TRUE),sep="-"))
aa$sdate<-as.Date(aa$SDATE)
plot(aa$sdate,aa$var1,xaxt="n")
library(plotrix)
# set the tick marks at the middle of each year
axis.dates<-as.Date(paste(1998:2012,6,30,sep="-"))
staxlab(1,axis.dates,1998:2012,nlines=3)

Obviously you don't want all of the months, so just add the months to the
years:

plot(aa$sdate,aa$var1,xaxt="n")
staxlab(1,axis.dates,format(axis.dates,"%b/%Y"),nlines=3)

Jim


On Tue, Feb 28, 2017 at 2:26 AM, Maria Lathouri via R-help
<r-help at r-project.org> wrote:
> Dear all,
> I have an excel file of 180 observations with dates and one variable, from
1998 to 2012 by random months (there are some years that I might not have all
the months or I might have two observations in one month). I am trying to plot
the dates in x axis and the variable in y axis. I have already used as.Date for
the dates so I can import them into R.
> Here is my script:> aa<-read.csv("aa.csv")>
attach(aa)> names(aa)#"SDATE" "var1"
> I convert the dates into R: > sdate<-as.Date(SDATE,
format="%Y-%m-%d")
>
> I am plotting the dates with my var1:> plot(sdate, var1,
type="l")
> Up to now, everything seems ok. However, in the x-axis I only get three
years, 2000, 2005 and 2010. As I want to show all the years or at least as many
as it could be, I am using the following:
>> plot(sdate, var1, type="l", xaxt="n")
>
>> d1<-c((sdate[1]), (sdate[183]))>
d2<-as.Date((d1[1])+365*(0:15))
>> axis(side=1, at=0:15, labels=strftime(d2, format="%Y"),
cex.axis=0.8,las=2);  I tried also to plot the dates in a month-Year form:
>
>> d2<-as.Date((d1[1])+150*(0:20))
>> plot(sdate, var1, type="l", xaxt="n")>
axis(side=1, at=0:15, labels=strftime(d2, format="%m-%Y"),
cex.axis=0.8,las=2)
>
> But nothing happened. I cannot understand why it doesn't show anything.
> I have attached the file as well in case you want to have a more clear
picture.
> I really appreciate it if you can help me on this.
> Thank you very much in advance.
> Kind regards,Maria
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