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

B Dittmann bd10stats at googlemail.com
Sat Apr 11 09:53:56 CEST 2015


Hi Ista

This works brilliantly and is so elegant!

Yes,  i googled quite a while but did not come across do.call till now.

Thanks again

Bernard
On 10 Apr 2015 22:46, "Ista Zahn" <istazahn at gmail.com> wrote:

> Hi Bernard,
>
> Did you try searching for an answer? This question (minus the xts part
> which I don't think will matter) has been asked and answered many times,
> with
>
> do.call("rbind", foo)
>
> being a common answer.
>
> Best,
> Ista
> On Apr 10, 2015 5:35 PM, "B Dittmann" <bd10stats at googlemail.com> wrote:
>
>> Dear R users,
>>
>> hope you can point me in the right direction. I am stuck with the
>> following
>> problem.
>>
>> 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
>> return(results)
>> }
>>
>> 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,
>>
>> Bernard
>>
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>>
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>

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