Your logic test is not correct. Here is what I think you want. See if it makes sense.
> x <- list() # create some test data > x[[1]] <- read.table(textConnection("1 2 3 4 + 5 6 7 8 + 4 3 2 1 + 8 7 6 5")) > # create another list element > x[[2]] <- t(x[[1]]) > str(x[[1]]) 'data.frame': 4 obs. of 4 variables: $ V1: int 1 5 4 8 $ V2: int 2 6 3 7 $ V3: int 3 7 2 6 $ V4: int 4 8 1 5 > x[[1]] V1 V2 V3 V4 1 1 2 3 4 2 5 6 7 8 3 4 3 2 1 4 8 7 6 5 > # assume all numeric -- test if any less than 3 > # case 1 > x[[1]] < 3 # you get multiple values back V1 V2 V3 V4 [1,] TRUE TRUE FALSE FALSE [2,] FALSE FALSE FALSE FALSE [3,] FALSE FALSE TRUE TRUE [4,] FALSE FALSE FALSE FALSE > # really want a single value > any(x[[1]] < 3) [1] TRUE > # I think this is what you want > newlist <- list() > if (any(x[[1]] > 1) & any(x[[2]] > 1)){ + newlist[[1]] <- x[[1]] - x[[2]] + } > newlist [[1]] V1 V2 V3 V4 1 0 -3 -1 -4 2 3 0 4 1 3 1 -4 0 -5 4 4 -1 5 0 On 10/15/07, Svempa <[EMAIL PROTECTED]> wrote: > > I have the following code: > > list1 <- list() > for (i in list.files(pattern="filename1")){ > x <- read.table(i) > list1[[i]] <- x > } > > list2 <- list() > for (i in list.files(pattern="filename2*")){ > x <- read.table(i) > list2[[i]] <- x > } > > anslist <- vector('list', length(list1)) > for(i in 1:length(list1)) > if (list1[[i]] & list2[[i]] >1) > anslist[[i]] <- list1[[i]] - list2[[i]] > > That, if at least one element in either of the lists is below 1, nothing > happens. I now get the warning message "the condition has length >1..." etc. > I would guess this is because list1 and list2 aren't really real matrices, > more references to files. How do I get around this? > > -- > View this message in context: > http://www.nabble.com/The-%22condition-has-length-%3E-1%22-issue-for-lists-tf4625785.html#a13209531 > 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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve? ______________________________________________ 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.