[R] how to create analog stripchart plots of x vs t (t=mm/dd/yyyy hh:mm:ss)

Richard Evans revans at jlab.org
Sat Mar 11 22:00:05 CET 2006


Hello r-experts,
I sure could us a little help.

I have an ever updating text file with timestamped data in it. I can
reformat in anyway I want if need be but currently I have chosen to make
columns of date, time and measuresed value (comma delimeted and with the
dates and times in quotes to interpret them as strings).

Here is a small section of my text data file:

"3/11/2006","15:09",0.014652
"3/11/2006","15:08",0.014652
"3/11/2006","15:06",0.000000
...etc...

I am trying to make a plot of 'X' vs. 't'
where 'x' is a simple numerical vector of N elemets
and 't'   is a timestamp like "mm/dd/yyyy hh:mm:ss"
(also of N elements)

here is how i am getting the data:
 >
 >TheData <- scan("MyDataFile.txt",sep=",",list("","",0))
 >TheDates <- TheData[[1]]
 >TheTimes <- TheData[[2]]
 >TheValue <- TheData[[3]]
 >
and here is how i am making the datetime objects:
 >
 >TimeStampStr <- paste(TheDates,TheTimes)
 >TimeStampObj <- strptime(xStamp,"%m/%d/%y %H:%M:%S")
 >
and then i try to plot it with:
 >
 >plot(TimeStampObj,TheValues)
 >
but this is where i get an error like this:
>
Read 54 records
Error in plot.window(xlim, ylim, log, asp, ...) :
        need finite 'ylim' values
In addition: Warning messages:
1: no finite arguments to min; returning Inf
2: no finite arguments to max; returning -Inf

Can someone help me understand what i need to do?
Am I going about this the wrong way?
Is there a smarter/more elegant way to do this?

And advice is greatly apreciated.

Sincerest thanks (in advance),
- revansx

P.S.
here is an small section of my input file:




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