[R] multiple input files single output - lapply? - pls advise

B Dittmann bd10stats at googlemail.com
Fri Apr 10 22:20:52 CEST 2015

Dear R users,

hope you can point me in the right direction. I am stuck with the following

My function "f1" reads csv files, manipulates them into the right xts
format and returns the output at the end. This works perfectly fine. Now, I
need to run "f1" over a long list of various csv files, all of the same
format, but different dates (or time stamps) which is guaranteed by design.
All these individual results per each file I hope to combine into one xts
or zoo object.

I tried "lapply" as follows:

# all csv files start with "z1":
file.names <- list.files(pattern = "z1*", full.names = T, recursive = FALSE)

# my function:
f1 <- function(x, param){
# x: the csv file
# param: some parameter for calculation
# spits results out

res <- lapply(file.names, function(x){f1(x, param)})

I wrote the output to "res" and by subsetting res[1], res[2], ... I can
retrieve the results of each individual csv file on which I applied my
function "f1".

How could I append or merge all individual results res[i] for my i csv
files into one xts or zoo object?

Many thanks in advance,


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