Re: [R] beginner's loop issue
Thank you all for your helpful comments!
I solved my problem by creating an empty matrix before the loop and
adjusting the loop itself, this is the code:
size - dim(input)
out - matrix('',nrow =size[1], ncol = 9)
for (i in 1:nrow(input)) {
out[i,1:3] - unlist(MyFunction(input[i,1],input[i,2], input[i,3])
out[i,4:6] - unlist(MyFunction(input[i,5],input[i,7], input[i,6])
out[i,7:9] - unlist(MyFunction(input[i,8],input[i,10], input[i,9])
}
It's probably not the most efficient way of doing it but it gives me the
desired output matrix...
Thanks for pointing me to this pdf R inferno pdf, I had an old version of
it..
I'm, starting to use R again after long time and this is a very useful
guide!
All the best
Ale
--
View this message in context:
http://r.789695.n4.nabble.com/beginner-s-loop-issue-tp4469514p4471352.html
Sent from the R help mailing list archive at Nabble.com.
__
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.
[R] beginner's loop issue
Dear All,
I hope you don't mind helping me with this small issue. I haven't been using
R in years and I'm trying to fill in a matrix
with the output of a function (I'm probably using the Matlab logic here and
it's not working).
Here is my code:
for (i in 1:length(input)){
out[i,1:3] - MyFunction(input[i,1],input[i,2], input[i,3])
out[i,4:6] - MyFunction(input[i,5],input[i,7], input[i,6])
out[i,7:9] - MyFunction(input[i,8],input[i,10], input[i,9])
}
'input' is a matrix
dim(input)
[1] 46 10
and each raw corresponds to a different subject.
The error I get here is
/Error in out[i, 1:3] - get.vaTer(input[i, 2], input[i, 4], input[i, 3], :
object 'out' not found/
So I wonder, what's wrong in the assignment to the variable out?
Should I define the variable before the loop?
Thanks for your help
Best
Ale
--
View this message in context:
http://r.789695.n4.nabble.com/beginner-s-loop-issue-tp4469514p4469514.html
Sent from the R help mailing list archive at Nabble.com.
__
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.
Re: [R] beginner's loop issue
Yes, the short answer is that you need to define out before running
the loop. The most effective way to do so will be to set up a matrix
with the exact right dimensions (if you know them up front); something
like out - matrix(NA, nrow = length(input), ncol = 9)
Michael
On Tue, Mar 13, 2012 at 12:27 PM, aledanda danda.ga...@gmail.com wrote:
Dear All,
I hope you don't mind helping me with this small issue. I haven't been using
R in years and I'm trying to fill in a matrix
with the output of a function (I'm probably using the Matlab logic here and
it's not working).
Here is my code:
for (i in 1:length(input)){
out[i,1:3] - MyFunction(input[i,1],input[i,2], input[i,3])
out[i,4:6] - MyFunction(input[i,5],input[i,7], input[i,6])
out[i,7:9] - MyFunction(input[i,8],input[i,10], input[i,9])
}
'input' is a matrix
dim(input)
[1] 46 10
and each raw corresponds to a different subject.
The error I get here is
/Error in out[i, 1:3] - get.vaTer(input[i, 2], input[i, 4], input[i, 3], :
object 'out' not found/
So I wonder, what's wrong in the assignment to the variable out?
Should I define the variable before the loop?
Thanks for your help
Best
Ale
--
View this message in context:
http://r.789695.n4.nabble.com/beginner-s-loop-issue-tp4469514p4469514.html
Sent from the R help mailing list archive at Nabble.com.
__
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.
__
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.
Re: [R] beginner's loop issue
On Tue, Mar 13, 2012 at 11:27 AM, aledanda danda.ga...@gmail.com wrote:
Dear All,
I hope you don't mind helping me with this small issue. I haven't been using
R in years and I'm trying to fill in a matrix
with the output of a function (I'm probably using the Matlab logic here and
it's not working).
Here is my code:
for (i in 1:length(input)){
out[i,1:3] - MyFunction(input[i,1],input[i,2], input[i,3])
out[i,4:6] - MyFunction(input[i,5],input[i,7], input[i,6])
out[i,7:9] - MyFunction(input[i,8],input[i,10], input[i,9])
}
'input' is a matrix
dim(input)
[1] 46 10
and each raw corresponds to a different subject.
The error I get here is
/Error in out[i, 1:3] - get.vaTer(input[i, 2], input[i, 4], input[i, 3], :
object 'out' not found/
out has to exist first, as previous commenter said.
Furthermore, suggestions:
Consider making MyFunction accept a vector of 3 arguments, rather than
separate arguments.
Consider making out 3 columns, as in
out - matrix(0, nrow=N, ncol=3)
for(i ...){
out[i,1:3] - MyFunction(input[i,1:3])
out[i,1:3] - MyFunction(input[i,4:6])
out[i,1:3] - MyFunction(input[i,7:9])
}
If you could re-shape your input thing as a list with one element
that needs to go into MyFunction, this could get easier still:
lapply(input, MyFunction)
or if input were an array with 3 columns, you could revise MyFuntion
to accept a 3-vector.
apply(input, 1, MyFunction)
Hardly ever in R does one need to specify inputs as you have done in
your example.
pj
--
Paul E. Johnson
Professor, Political Science Assoc. Director
1541 Lilac Lane, Room 504 Center for Research Methods
University of Kansas University of Kansas
http://pj.freefaculty.org http://quant.ku.edu
__
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.
