R help - Sep 2011 - Problem looping a function to create/add to new dataframe

Dear List Members,

I have created a function to run a simulation based on a given set of 
values within a vector, such that I run the function like this:

new.data<-sapply(vector, function)

In which I run 'function' on every value within a vector that I created.
The result is a matrix of 1000 rows, and as many columns as the length 
of the vector.

I modified the function to utilize two given values, such that it is: 
function(x,y), and I want to run this function for not only a range of 
values of 'x', but a range of values of 'y' as well, such that
for each
value of 'y', I'd create another 1000 rows in the matrix. I was
trying
to loop this, but in doing so, it looks like I just keep creating 
datasets and replacing them with datasets for subsequent 'y' values, 
rather than adding new rows. The structure of my current loop is below. 
Any suggestions on what to change to accomplish what I want? Would it be 
good to create a dataframe first and then somehow add these new rows to 
the dataframe? Also, is it appropriate to have the 'i' in the sapply 
statement?

for (i in c(seq(10,100,10))){
         new.data<-sapply(vector, function, i)
     }

Please let me know if more detail on my code would be helpful- I was 
just trying to keep it simple and focus on what I saw as the problem at 
hand for now.
Thank you for your help.
Sincerely,
Mike Treglia

-- 
Michael Treglia
Applied Biodiversity Sciences NSF-IGERT Program
Wildlife and Fisheries Sciences
Texas A&M University
Lab: (979)862-7245
mlt35 at tamu.edu
http://people.tamu.edu/~mlt35

It would seem you want something like this:

new.data <- sapply(seq(10, 100, 10), function(i) sapply(vector, yourFunc, i))


On Thu, Sep 15, 2011 at 1:50 PM, Mike Treglia <mlt35 at tamu.edu>
wrote:
> Dear List Members,
>
> I have created a function to run a simulation based on a given set of
values
> within a vector, such that I run the function like this:
>
> new.data<-sapply(vector, function)
>
> In which I run 'function' on every value within a vector that I
created. The
> result is a matrix of 1000 rows, and as many columns as the length of the
> vector.
>
> I modified the function to utilize two given values, such that it is:
> function(x,y), and I want to run this function for not only a range of
> values of 'x', but a range of values of 'y' as well, such
that for each
> value of 'y', I'd create another 1000 rows in the matrix. I was
trying to
> loop this, but in doing so, it looks like I just keep creating datasets and
> replacing them with datasets for subsequent 'y' values, rather than
adding
> new rows. The structure of my current loop is below. Any suggestions on
what
> to change to accomplish what I want? Would it be good to create a dataframe
> first and then somehow add these new rows to the dataframe? Also, is it
> appropriate to have the 'i' in the sapply statement?
>
> for (i in c(seq(10,100,10))){
> ? ? ? ?new.data<-sapply(vector, function, i)
> ? ?}
>
> Please let me know if more detail on my code would be helpful- I was just
> trying to keep it simple and focus on what I saw as the problem at hand for
> now.
> Thank you for your help.
> Sincerely,
> Mike Treglia
>
> --
> Michael Treglia
> Applied Biodiversity Sciences NSF-IGERT Program
> Wildlife and Fisheries Sciences
> Texas A&M University
> Lab: (979)862-7245
> mlt35 at tamu.edu
> http://people.tamu.edu/~mlt35
>
> ______________________________________________
> R-help at 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.
>


-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?

On Sep 15, 2011, at 1:50 PM, Mike Treglia wrote:
> Dear List Members,
>
> I have created a function to run a simulation based on a given set  
> of values within a vector, such that I run the function like this:
>
> new.data<-sapply(vector, function)
>
> In which I run 'function' on every value within a vector that I  
> created. The result is a matrix of 1000 rows, and as many columns as  
> the length of the vector.
>
> I modified the function to utilize two given values, such that it  
> is: function(x,y), and I want to run this function for not only a  
> range of values of 'x', but a range of values of 'y' as
well, such
> that for each value of 'y', I'd create another 1000 rows in the
> matrix. I was trying to loop this, but in doing so, it looks like I  
> just keep creating datasets and replacing them with datasets for  
> subsequent 'y' values, rather than adding new rows. The structure
of
> my current loop is below. Any suggestions on what to change to  
> accomplish what I want? Would it be good to create a dataframe first  
> and then somehow add these new rows to the dataframe? Also, is it  
> appropriate to have the 'i' in the sapply statement?
>
> for (i in c(seq(10,100,10))){
The c() call is extraneous.
>        new.data<-sapply(vector, function, i)


Perhaps:

# scrap the entire for loop(sapply()) mess and use this

newdata <- outer(Y=seq(10,100,10), X=vector, FUN=function)

Or:

mapply(function,  expand.grid(x=vector, y=seq(10,100,10) ) )
# which is sort of like your last notion,

All of this is untested in the absence of a reproducible example but  
you definitely should work through the examples on:

?outer
?mapply

>    }
>
> Please let me know if more detail on my code would be helpful- I was  
> just trying to keep it simple and focus on what I saw as the problem  
> at hand for now.
> Thank you for your help.
> Sincerely,
> Mike Treglia
>
> -- 
> Michael Treglia
> Applied Biodiversity Sciences NSF-IGERT Program
> Wildlife and Fisheries Sciences
> Texas A&M University
> Lab: (979)862-7245
> mlt35 at tamu.edu
> http://people.tamu.edu/~mlt35
>
> ______________________________________________
> R-help at 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.
David Winsemius, MD
West Hartford, CT