[R] jpeg, dev.off() inside function

[Henrik Bengtsson]

In your function, split up your code in two lines as:

pathname <- paste("test ", deparse(substitute(series)), i, ".jpg");
jpeg(filename=pathname, width=1200, height=800, pointsize=12,
quality=400, bg="white");

The focus on what 'pathname' is/becomes when you put it inside your
function.  That will help you troubleshoot.  It has most likely
nothing to do with the jpeg() function.

My $.02

/Henrik

PS. 'series' is not set inside the function if there are not two columns. DS.


On Tue, Aug 19, 2008 at 6:09 AM, marciarr <marcia.rocha at gmail.com> wrote:
>
> Dear all,
> I am trying to plot and save the plots. I have written a small function for
> that in which I use the jpeg and dev.off() commands. Strangely, when these
> commands are inside the function, they are not working anymore.
> For instance:
>
> dataframe<- data.frame (x=c(1:20),y=seq(0,9.5, length=20))
>
> for (i in seq(0,15, length=4)){
>        setwd ("C:/R")
>        jpeg(filename = paste("test ",deparse(substitute(series)),
>        i, ".jpg"), width = 1200,
>        height = 800,pointsize = 12, quality = 400, bg = "white")
>        plot(dataframe[1+i:((nrow(z)/4)+i),], type="l")
>        dev.off()}
>
> This works perfectly. But if I try to make a function out of it, such as:
>
> X<-function (x, y = NULL, plot = TRUE, na.action = na.fail)
> {
>       if (NCOL(x) == 2) {
>        series <- deparse(substitute(x))
>        }
>        for (i in seq(0,15, length=4)){
>        setwd ("F:/R/P to B manuscript/area under the curve")
>        jpeg(filename = paste("test ",deparse(substitute(series)),
>        i, ".jpg"), width = 1200,
>        height = 800,pointsize = 12, quality = 400, bg = "white")
>        plot(z[1+i:((nrow(z)/4)+i),], type="l")
>        dev.off()}
>        return(dataframe)}
>
> and try to run:
> X(dataframe)
> I get this error message:
>
> Error in jpeg(filename = paste("test ", deparse(substitute(series)), i,  :
>  unable to start device devWindows
> In addition: Warning message:
> In jpeg(filename = paste("test ", deparse(substitute(series)), i,  :
>  Unable to open file 'test  "dataframe" 0 .jpg' for writing
>
> Could anyone help me???
> Thank you and have a nice day,
> Marcia
> --
> View this message in context: http://www.nabble.com/jpeg%2C-dev.off%28%29-inside-function-tp19048365p19048365.html
> Sent from the R help mailing list archive at Nabble.com.
>
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