R help - Jul 2009 - abline(v= x) in plot with time formated xaxis not working

Hi,

I try to create a vertical line in my plot, which has a xaxis comprising
time formated data.

This is what I tried:

----------------

y<-152833
x<-strptime(y, format="%H%M%S")

abline(v=x, col="red")

----------------

for some reason, it doesn't work and no error msg is displayed...

I hope someone can tell me what I do wrong, or maybe an alternative.

Thanks in advance!!

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On Jul 15, 2009, at 5:25 PM, F!! wrote:
>
> Hi,
>
> I try to create a vertical line in my plot, which has a xaxis  
> comprising
> time formated data.
>
> This is what I tried:
>
> ----------------
>
> y<-152833
> x<-strptime(y, format="%H%M%S")
>
> abline(v=x, col="red")
But, but, but ... where is your plot function?

>
> ----------------
>
> for some reason, it doesn't work and no error msg is displayed...
>
> I hope someone can tell me what I do wrong, or maybe an alternative.
>
> Thanks in advance!!

David Winsemius, MD
Heritage Laboratories
West Hartford, CT

Dear Fritz,

(had to guess the name as well as most of the other things not given)

On Wed, 15-Jul-2009 at 02:25PM -0700, F!! wrote:

|> 
|> Hi,
|> 
|> I try to create a vertical line in my plot, which has a xaxis comprising
|> time formated data.
|> 
|> This is what I tried:
|> 
|> ----------------
|> 
|> y<-152833
|> x<-strptime(y, format="%H%M%S")
|> 
|> abline(v=x, col="red")
|> 
|> ----------------
|> 
|> for some reason, it doesn't work and no error msg is displayed...

My guess is that you don't already have a plot, or if you do, your
value of x is outside the range it covers.

Try par()$usr and see if my guess is correct.  There's no way I can
tell.


|> 
|> I hope someone can tell me what I do wrong, or maybe an alternative.

If you had a reproducible example, they'd be in a better position.


|> ______________________________________________
|> R-help at r-project.org mailing list
|> https://stat.ethz.ch/mailman/listinfo/r-help
|> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
|> and provide commented, minimal, self-contained, reproducible code.

Notice the last line?



-- 
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 _( Y )_  	         Average minds discuss events 
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 (_)-(_)  	                      ..... Eleanor Roosevelt
	  
~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.

Sorry for the lack of the plot. It's is just a simple xy plot with xvalues
formated as shown in my post (strptime()).

Anyway, here a working example:


> 
> rm(list=ls())
> 
> x<-c(100*1500:1559, 100*1600:1659)
> x<-strptime(x, format="%H%M%S")
> y<-c(CO2$conc, CO2$conc[1:36])
> 
> plot(x, y, pch=18, type="p", ylab="yfoo",
xlab="xfoo", yaxs="r")
> 
> abline(h=100, v=0, col="gray60", lty=2)
> text.xvalue<-151500
> text.xvalue<-strptime(text.xvalue, format="%H%M%S")
> text(text.xvalue, 80, "detection threshold",
col="gray60", cex=0.8)
> 
> event.1<-152833
> event.1<-strptime(event.1, format="%H%M%S")
> abline(v=event.1, col="red")
> 
> 
The format for the xvalues works in the case of text positioning, but
doesn't in the case of abline. 

JimHoltman replied this topic via email with a solution:

<-as.POSIXct(strptime(y, format="%H%M%S"))


I still don't know why this second function is necessary since everything
works without it, except for the abline-thing...

Nevertheless, thanks for all the suggestions!

Fritz
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