[R] skip reading a file.

Duncan Murdoch murdoch.duncan at gmail.com
Tue May 24 12:43:41 CEST 2011


On 11-05-24 6:00 AM, Alaios wrote:
> Dear all,
> I would like to do read a bunch of files that have the following format
>
> file_i_j
> examples:
> file_1_1
> file_1_2
> file_1_3
> file_2_1
> file_2_2
> file_3_1
> file_3_2
> file_3_3
> file_3_4
> file_4_1
> file_4_2
>
> The integer i goes from 1 to 100
> and the integer j starts from 1 and stops somewhere between 1 and 100, which I do not know in advance
>
> Usually I would be able to solve this by having a nested loop
>
> (algorithmic syntax below, not sure if is R okay)
> for i in (c(1:100))
>    for j in (c(1:100))
>      store[i,j]<- read file_i_j
>     end
> end
>
> the problem with that is that R will halt when j take a value that refers to a non existing value. Thus I want to have a good way to break the nested loop and continue with the outer one. How I can do that?

Use a while() loop, or use break.  You can test for the existence of a 
file using the file.exists() function.

Duncan Murdoch



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