[R] R GUI plot by color

[Jim Lemon]

Hi jpara3,
Your example, when I got it to go:

one<-c(3,2,2)
two<-c("a","b","b")
data<-dataframe(one,two)
plot(data$one,col=data$two)

does indeed work, and I'll explain how. You are plotting the values of
data$one against the _values_ of data$two (see point 3 of my
response). In this case, the values of data$two are of class "factor",
which means that they have numeric values attached to the levels (a,
b) of the factor. When you pass these values as the "col" argument,
they are silently converted to their numeric values (1,2,2). In the
default palette, these numbers represent the colors - black, red, red.
Those are the colors in which the points are plotted. So far, so good.
Let's look at the other two points that I guessed.

1) The column names of data2 are not numbers

colnames(data)
[1] "one" "two"

As you can see, the column names are character variables, and they
don't translate to numbers:

as.numeric(colnames(data))
[1] NA NA

2) The number of columns in data2 is not equal to the number of values
in data1 that you are plotting

It's pretty obvious that there are two values in the column names and
three in the vector of values that you are plotting in your
example.So, I think I got three out of three without knowing what the
data were.

Jim


On Fri, Jul 24, 2015 at 7:53 PM, jpara3 <j.para.fernandez at hotmail.com> wrote:
> I have done a trial with a dataframe like this:
> one<-c(3,2,2)
> two<-c(a,b,b)
> data<-dataframe(uno,dos)
>
> plot(data$one,col=data$two)
>
> and it plots perfect.
>
> If I try it with the code that i have post in the first message, selecting
> data1 and data2 as i nthis example, the plot is plotted, but all dots with
> the same color.
>
> Thanks for the answer but noone of the 3 topics is the root problem.
>
>
>
>
>
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