[R] trouble with for loop

[Peter Alspach]

?try 

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of Kyeongmi Cheon
> Sent: Thursday, 6 November 2008 4:56 p.m.
> To: R help mailing list
> Subject: [R] trouble with for loop
> 
> Hello,
> I'm having two similar problems with for loop and I would 
> appreciate any help or comment.
> 
> I want to use  "for loop" to calculate series of initial 
> values for an optimization problem. But
> 
> some initial values have my function quit due to problems 
> like calculating the inverse of singular
> 
> matrices. I don't want to make my program check determinants 
> and skip it if it
> 
> is very small. My program stopping for certain iterations is 
> okay but my problem is that the whole
> 
> for loop is ended from there and it does not move to the next 
> iteration. So the rest of the initial values are
> 
> never tried. Here is a simple example:
> 
> 
> 
> mat.inv <- function(theta){
>    mat1 <- matrix( theta, nr=2)
>    inv <- solve(mat1)
>    res <- theta[1]+inv[1,1]
>    res
> }
> 
> for (i in 1:7){
>    theta4 <- i
>    theta.vec <-  c(1,2,2,theta4)
>    theta.res <- mat.inv(theta.vec)
>    write.table(theta.res, paste("result",i,".txt",sep="")) }
> 
> It stops when i=4. I need to try other values. How would I 
> get it to simply move on to the next
> 
> iteration :i=5,6,7 without checking determinants?
> 
> 
> 
> Another similar problem that I have is that I have thousands 
> of txt files and want to use a for loop
> 
> to read them into R. The file names are consecutive but some 
> of them are missing: For
> 
> example, they are "result1.txt", "result2.txt", 
> "result3.txt", "result5.txt"...  When I use for loop to read 
> it, it gets an error at "result4.txt" so that 
> "result5.txt"...  are not read. I attached an example program 
> here. Could anyone help me? I appreciate your time in advance.
> Kyeongmi
> 
> 
> #create dataset name
> for (i in 1:6){
> assign(paste("newname",i,sep=""), paste("result",i,".txt",sep="")) }
> ls()
> 
> #read data if there are files with the name: "result1.txt", 
> "result2.txt", "result3.txt",
> 
> "result5.txt".
> for (i in 1:6){
>       assign(  paste("r",i,sep=""),
> read.table(get(paste("newname",i,sep="")), header=T)    )
> 
> }
> 
> # It stops at "result3.txt" so that "result5.txt"...  are not read.
> 
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