[R] if/else for plot/lines?

[Julian Burgos]

The simplest way would be to have a flag, an indicator variable that 
stores a value that indicates if a plot has been done before.  Something 
like this

plot (do my first plot here...)
is.plot=T

.... later in the code...

if (is.plot) {plot (do new plot here)} else {lines(add lines to the 
previous plot)}


Julian


Roger Levy wrote:
> I'm interested in writing a function that constructs a new plot on the
> current graphics device if no plot exists there yet, but adds lines to
> the existing plot if a plot is already there.  How can I do this?  It
> seems to me that the exists() function might be co-opted to do this, but
> it's not obvious how.
>
> Many thanks,
>
> Roger
>
>   

-- 
Julian M. Burgos

Fisheries Acoustics Research Lab
School of Aquatic and Fishery Science
University of Washington

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Seattle, WA  98105 

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