On 2011-01-17 22:48, Ben Harrison wrote:
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.
Since you don't provide data, let's borrow from the
help(droplevels) page:
aq <- transform(airquality,
Month = factor(Month, labels = month.abb[5:9]))
str(aq)
#'data.frame': 153 obs. of 6 variables: |
# $ Ozone : int 41 36 12 18 NA 28 23 19 |
# $ Solar.R: int 190 118 149 313 NA NA 29 |
# $ Wind : num 7.4 8 12.6 11.5 14.3 14. | etc
# $ Temp : int 67 72 74 62 56 66 65 59 |
# $ Month : Factor w/ 5 levels "May","Jun |
# $ Day : int 1 2 3 4 5 6 7 8 9 10 ... |
Now see if the following give you some R inspiration:
plot(Ozone ~ Temp, data = aq)
plot(Ozone ~ Temp, data = aq, subset = {Month == "Sep"})
boxplot(Ozone ~ Month, data = aq)
boxplot(Ozone ~ Month, data = aq,
subset = {Month != "Aug"})
boxplot(Ozone ~ Month, data = aq,
subset = {!(Month %in% c("Jul", "Aug"))})
boxplot(Ozone ~ Month,
data = droplevels(subset(aq, subset = {Month != "Aug"})))
boxplot(Ozone ~ Month,
data = droplevels(subset(aq, !(Month %in% c("Jul", "Aug")))))
BTW, attach() is not usually a good idea; have a look at ?with.
Peter Ehlers
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