David Winsemius wrote:
On Jul 5, 2009, at 9:53 AM, Mark Knecht wrote:
On Sat, Jul 4, 2009 at 5:22 PM, jim holtman<jholt...@gmail.com> wrote:
See if this example helps; show how to either plot the row or columns
of a data frame:
test <- data.frame(C1=runif(10), C2=runif(10), C3=runif(10))
test
C1 C2 C3
1 0.91287592 0.3390729 0.4346595
2 0.29360337 0.8394404 0.7125147
3 0.45906573 0.3466835 0.3999944
4 0.33239467 0.3337749 0.3253522
5 0.65087047 0.4763512 0.7570871
6 0.25801678 0.8921983 0.2026923
7 0.47854525 0.8643395 0.7111212
8 0.76631067 0.3899895 0.1216919
9 0.08424691 0.7773207 0.2454885
10 0.87532133 0.9606180 0.1433044
# this will plot each column (C1, C2, C3)
matplot(test, type='o')
# plot each row
matplot(t(test), type='o')
On Sat, Jul 4, 2009 at 8:02 PM, Mark Knecht<markkne...@gmail.com> wrote:
OK, I guess I'm getting better at the data part of R. I wrote a
program outside of R this morning to dump a bunch of experimental
data. It's a sort of ragged array - about 700 rows and 400 columns,
but the amount of data in each column varies based on the length of
the experiment. The real data ends with a 0 following some non-zero
value. It might be as short as 5 to 10 columns or as many as 390. The
first 9 columns contain some data about when the experiment was run
and a few other things I thought I might be interested in later. All
the data starts in column 10 and has headers saying C1, C2, C3, C4,
etc., up to C390 The first value for every experiment is some value I
will normalize and then the values following are above and below the
original tracing out the path that the experiment took, ending
somewhere to the right but not a fixed number of readings.
R reads it in fine and it looks good so far.
Now, what I thought I might do with R is plot all 700 rows as
individual lines, giving them some color based on info in columns 1-9,
but suddenly I'm lost again in plots which I think should be fairly
easy. How would I go about creating a plot for even one line, much
less all of them? I don't have a row with 1,2,3,4 to us as the X axis
values. I could go back and put one in the data but then I don't think
that should really be required, or I could go back and make the
headers for the whole array 1:400 and then plot from 10:400 but I
thought I read that headers cannot start with numbers.
Maybe the X axis values for a plot can actually be non-numeric C1, C2,
C3, C4, etc and I could use line (C1,0) to (C2,5) and so on? Or maybe
I should strip the C from C1 and be left with 1? Maybe the best thing
is to copy the data for one line to another data.frame or array and
then plot that?
Just sort of lost looking at help files. Thanks for any ideas you can
send along. Ask questions if I didn't explain my problem well enough.
Not looking for anyone to do my work, just trying to get the concepts
right
Cheers,
Mark
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--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
Hey Jim,
Thanks for the pointers on matplot. I suspect that will be useful
one of these days.
I'm attaching a little code to make a test case closer to what I
have to deal with at the bottom. My problem with your data was that
you plot everything. In my data I need to plot only a portion of it,
and in the array not every cell is valid - I don't want to plot cells
that have 0.00 as a value. In the array 'test' I need to plot the
general area defined by C1:C6, each row as a line, but stop plotting
each row when I run into a 0. Keep in mind that I don't know what
column C1 starts in. It is likely to change over time.
I think the root cause of a number of my coding problems in R right
now is my lack of skills in reading and grabbing portions of the data
out of arrays. I'm new at this. (And not a programmer) I need to find
some good examples to read and test on that subject. If I could locate
which column was called C1, then read row 3 from C1 up to the last
value before a 0, I'd have proper data to plot for one line. Repeat as
necessary through the array and I get all the lines. Doing the lines
one at a time should allow me the opportunity to apply color or not
plot based on values in the first few columns.
Thanks,
Mark
test <- data.frame(A=1:10, B=100, C1=runif(10), C2=runif(10),
C3=runif(10), C4=runif(10), C5=runif(10), C6=runif(10))
test<-round(test,2)
#Make array ragged
test$C3[2]<-0;test$C4[2]<-0;test$C5[2]<-0;test$C6[2]<-0
test$C4[3]<-0;test$C5[3]<-0;test$C6[3]<-0
test$C6[7]<-0
test$C4[8]<-0;test$C5[8]<-0;test$C6[8]<-0
#Print array
test
?"[" for the help page on Extract which is a gold mine of useful methods
A single row can be extracted with:
test[3, ]
Two rows:
test[3:4, ]
And individual elements of a vector can be further specified:
> test[3,][4:5]
C2 C3
3 0.66 0.51
You can then access or determine numerical values with logical functions
such as which:
which(names(test)=="C1") # 3 names gives you an ordered listing of
column names
which(test[3,] == 0.0) # 6,7
(Note: one of the most frequent newbie questions is why some seemingly
obvious equality expressions are FALSE):
> sqrt(2)*sqrt(2) == 2
[1] FALSE
So if your values are calculated from other values then consider using
all.equal()
And repeated applications of the testing criteria process are effective:
test[3,][which(names(test)=="C1"):(which(test[3,] == 0.0)-1)]
C1 C2 C3
3 0.52 0.66 0.51
(and a warning that does not seem accurate to me.)
In which(names(test) == "C1"):(which(test[3, ] == 0) - 1) :
numerical expression has 3 elements: only the first used
David,
# which(test[3,] == 0.0)
[1] 6 7 8
and in a:b a and b must be length 1 vectors (scalars) otherwise just the
first element (in this case 6) is used.
That leads us to the conclusion that writing the line above is not
really the cleanest way or you intended something different ....
Best,
Uwe
Seems to me that all of the element were used. I cannot explain that
warning but am pretty sure it can be ignored.
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
