R help - Feb 2011 - (no subject)

Hey,

I am trying to graph a series of XY plots from a set of .csv files. Getting the
csv files read in and the original plot set up is not a problem, but I cannot
figure out a way to call get(iterator) within a separate dataset. A chunk of my
code is below.


data <- read.csv(file= filename)
data2 <- read.csv(file= filename2)

names <- names(data)
attach(data)

for (item in names) {
    jpeg(filename=sprintf(directory_%s.jpg, item)
    plot(SiO2, get(item), pch="", ylab=sprintf("%s", item))
    points(alith$SiO2, alith$get(item), pch=21, col="red")
    points(blith$SiO2, blith$get(item), pch=21, col="blue")
    points(clith$SiO2, clith$get(item), pch=21, col="green")
    points(dlith$SiO2, dlith$get(item), pch=21, col="orange")
    points(glith$SiO2, glith$get(item), pch=21, col="red4")
    points(hlith$SiO2, hlith$get(item), pch=21, col="purple")
    points(llith$SiO2, llith$get(item), pch=21)
    dev.off()
}

Ideally this would spit out hundreds of xy plots (and it does work if I plot
them all in the same color by turning the pch="" off. However, when
calling from a dataset with $, it will not let you use a function as the
argument (the get(item) part gives an error). Is there any way around this?

Thanks

Taylor

First of all I would advice you to use meaningful subjects when posting 
to the list.

My second point is only a vague guess, but if you use the exact code 
that you posted there may be bracket missing....(its the closing bracket 
of the jpg() call ). May this produce your error?

Third, you should use [[]] instead of $ to access the elements of the 
data frame ( see ?$ ). blith[[item]] should do the job.


HTH
Jannis

On 02/14/2011 07:33 AM, Smith, Taylor Taran wrote:
> Hey,
>
> I am trying to graph a series of XY plots from a set of .csv files. Getting
the csv files read in and the original plot set up is not a problem, but I
cannot figure out a way to call get(iterator) within a separate dataset. A chunk
of my code is below.
>
>
> data<- read.csv(file= filename)
> data2<- read.csv(file= filename2)
>
> names<- names(data)
> attach(data)
>
> for (item in names) {
>      jpeg(filename=sprintf(directory_%s.jpg, item)
>      plot(SiO2, get(item), pch="", ylab=sprintf("%s",
item))
>      points(alith$SiO2, alith$get(item), pch=21, col="red")
>      points(blith$SiO2, blith$get(item), pch=21, col="blue")
>      points(clith$SiO2, clith$get(item), pch=21, col="green")
>      points(dlith$SiO2, dlith$get(item), pch=21, col="orange")
>      points(glith$SiO2, glith$get(item), pch=21, col="red4")
>      points(hlith$SiO2, hlith$get(item), pch=21, col="purple")
>      points(llith$SiO2, llith$get(item), pch=21)
>      dev.off()
> }
>
> Ideally this would spit out hundreds of xy plots (and it does work if I
plot them all in the same color by turning the pch="" off. However,
when calling from a dataset with $, it will not let you use a function as the
argument (the get(item) part gives an error). Is there any way around this?
>
> Thanks
>
> Taylor
>
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