hello, I am very new to R.
My current data set is a mix of values and categories. It is a geoscience
data set, with values per rock sample. Case in point, each sample belongs to
a lithology class, and each sample has several physical property
measurements (density, porosity...).

I want to be able to plot these physical properties for all samples in each
lithology class. this is how i'm doing it now:

> tc = read.table(....)
> attach(tc)
> names(tc)
tc = [1] "Well"            "Depth"           "Latitude"
"Longitude"
 [5] "Formation"       "Lithology"       "LithClass"       "CondUncert"
 [9] "sample.ID" "Conductivity"    "Density"         "Porosity"

> plot(Depth[LithClass=='sand'], Conductivity[LithClass=='sand'])
(ad nauseum... how can I loop through them all?)

and ...

> boxplot(Conductivity[LithClass=='clay'])
> boxplot(Conductivity~LithClass)    #  whole set of boxplots on one
diagram, but
    # what if want to exclude one or two of the LithClasses?

and ...

> pairs(c(tc[10],tc[2],tc[11],tc[12]))
this is as advanced as I've got.

Any tips would be greatly appreciated.

Ben.

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