On Aug 11, 2010, at 7:51 PM, Lorenzo Cattarino wrote:
Hi R-users,
I have a function (myfun) that I want to apply to the rows of a
matrix.
Basically, "myfun" takes the values from the matrix ("exp.des"), which
represent the different combinations of my experimental design, and
pass
them as arguments to some other functions (fun1 and fun2). As I want
to
replicate the results of fun1 and fun2 a certain number of time (e.g.
5), I have a for loop within myfun.
I would like to store the results of each iteration of fun1 and fun2
in
a separate matrix ("output") but I have some problems telling R
which is
the position of "output" where to store the results. It seems that
every
time "myfun" is applied to each row of "exp.des", the position
restarts
from 1, without being updated (like I am trying to make it doing).
Here
is an example of what I am talking about:
output <- matrix (, 15, 1)
index <- 1
myfun <- function(x)
{
bla # goes against the Posting Guide directive to produce
reproducible code
bla # ... if it doesn't matter than leave it out or use "#"
bla
...
for (i in 1:Rep) # Rep not defined
# the blank lines are also a barrier to comprehension
{
res1 <- fun1(....) # more useless junk
res2 <- fun2(res1,....)
output [index,1]<- res2$something
index <- index+1
}
return(output) # so you will get one of "output" per line of
matrix or dataframe
# But /// ... it does not (or at least should not in my understanding
of scoping) go into in that "output" object that you defined outside
the "myfun" function.
}
apply(exp.des, 1, myfun)
Would do absolutely nothing since you did not assign the output of the
"output's from apply() to any object. Lexical scoping. If you do not
understand the term then do some more reading.
Learn to post in plain text please. This is a plain text mailing
list. Ix-nay on the T-M-L-Hay.
[,1] [,2] [,3]
[1,] 23 5 99
[2,] 6 45 18
[3,] 1 65 9
[4,] 9 10 45
[5,] 3 30 9
[6,] NA NA NA
[7,] NA NA NA
[8,] NA NA NA
[9,] NA NA NA
[10,] NA NA NA
[11,] NA NA NA
[12,] NA NA NA
[13,] NA NA NA
[14,] NA NA NA
[15,] NA NA NA
I would like to have just one column with the three groups of five
values.
Many thanks
Lorenzo
\
David Winsemius, MD
West Hartford, CT
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