How can I run a simulation with the "try" function in R and keep only the results that worked

Question

I am using the 'try' function to create some subsets but I cannot manage to keep only the results taht worked with the 'try' function. Below is the line of code I have.

list_shp_Deforested_2000_Africa <- lapply(list_shp_FC_Africa, function(x){try(x[x$D_90_00!=100,],)})

Does somebody know the function which will allow me to keep only the result that worked? Thanks for your help?

Here's how I do this. http://stackoverflow.com/q/4948361/210673 — Aaron left Stack Overflow, Dec 02 '14 at 19:01

score 1 · Accepted Answer · answered Dec 02 '14 at 16:54

When you ask about the try function, you should read help(try) first. The last line in the examples does what you are interested in (where you should substitute list_shp_Deforested_2000_Africa for res).

unlist(res[sapply(res, function(x) !inherits(x, "try-error"))])

score 1 · Answer 2 · answered Dec 02 '14 at 17:51

You can Filter the list to not include those that inherit "try-error"

Filter(function(x) !inherits(x, "try-error"), list_shp_Deforested_2000_Africa)

Or, if you used tryCatch and return NULL if there is an error, it might be cleaner

L <- lapply(1:10, function(x) tryCatch(if(runif(1) > 0.5) stop() else 42, error=function(e) NULL))
Filter(length, L)

How can I run a simulation with the "try" function in R and keep only the results that worked

2 Answers2