[R] Using multiple dat files

[Bert Gunter]

"It seems therefore that there is no other way than read in individually >
100 weather tables using read.tables., right? Using file.choose() doesn't
change the work."

Yes. With that many files, file.choose() does not make sense. However, I
still do not understand what is the problem with using lapply() on the
character vector of file names with read.table() as you did in your
original post to read in all the files as components of the W list. As data
frames are also lists, you can extract individual columns as you did before
using  the $ extractor, i.e. W[[1]]$year, etc.. You can also use data frame
indices for the columns, i.e. W[[1]][ ,1] or W[[1]][ ,"year"] . All of
which I believe you know.

However, I will hazard a *guess* (so exercise due diligence and check) as
to the cause of your original error,

"dd(data = W[[1]]$Precip, time.scale = W[[1]]$year)
Fehler in W[[1]]$year : $ operator is invalid for atomic vectors'

even though I know **nothing** about the dd() function. My guess is:
"data" is usually an argument to a function that tells it to use
"nonstandard evaluation" to look for arguments and other names in the
function first in the "data" argument, rather than by following R's
"standard" evaluation by looking first through the function's closures.
**If** this guess is correct, the call you gave above should be something
like:

dd(data = W[[1]], time.scale = year, precip = Precip,...)

where precip (small "p") is a formal argument of the dd() function and
Precip is a column in the data frame W[[1]].  If this is wrong, my
apologies, and feel free to ignore without responding.

Best,
Bert

On Wed, Nov 6, 2024 at 10:59 AM Sibylle Stöckli <sibylle.stoeckli using gmx.ch>
wrote:

> Dear Rui
> Dear Bert
>
> Many thanks
>
> Solution
> filelist <- list.files(path =
> "O:/Data-Work/2.../Daten_RA-MeteoCH_1990-2021", pattern='*.dat', all.files=
> T, full.names= T)
> AAR<-read.table(filelist[1])
>
> It seems therefore that there is no other way than read in individually >
> 100 weather tables using read.tables., right? Using file.choose() doesn't
> change the work.
>
> Yes my .dat files are data.frames
>
> > str(W[[1]])'data.frame':	11688 obs. of  7 variables:
>  $ year  : num  1990 1990 1990 1990 1990 1990 1990 1990 1990 1990 ...
>  $ DOY   : num  1 2 3 4 5 6 7 8 9 10 ...
>  $ Ta    : num  -2.67 -2.77 -2.23 -2.21 -0.98 0.82 0.49 -1.02 -2.31 -3.36 ...
>  $ Tmin  : num  -3.5 -3.7 -4.26 -2.87 -2.98 0.3 -0.83 -1.27 -3 -3.82 ...
>  $ Tmax  : num  -1.13 -0.15 -0.13 -0.45 1 1.87 1.72 -0.35 -0.85 -2.3 ...
>  $ Precip: num  0 0 0 0 0.45 1.81 0.03 0 0 0 ...
>  $ rSSD  : num  0 0.08 0 0 0.08 0 0 0 0 0 ...
>
>
> *Gesendet: *Mittwoch, 6. November 2024 um 18:28
> *Von: *"Bert Gunter" <bgunter.4567 using gmail.com>
> *An: *"Sibylle Stöckli" <sibylle.stoeckli using gmx.ch>
> *CC: *r-help using r-project.org
> *Betreff: *Re: [R] Using multiple dat files
> Not quite sure if I understand you.
>
> list.files() simply returns a character vector(not a list). You can simply
> use a vector index to select whatever file you wish to read. So if your
> desired filename is the 5th element of filelist above, something like
>
> myfile <- read.table(filename[5], ...)
>
> You can also use regular expressions to choose a bunch of files that have
> some common signature to their names that you can read in simultaneously
> using your "filelist" vector of names via something like:
>
> myfiles <- lapply(grep("weath", filelist, value = TRUE), \(x)
> read.table(x,...))
> ### Note that the result of lapply *is* a list, so use list indexing for
> extraction from myfiles.
>
>
> You can also choose files to read interactively (via a GUI interface)
> using file.choose() instead of using list.files() if you prefer to do it
> that way.
>
> Cheers,
> Bert
>
> On Wed, Nov 6, 2024 at 8:25 AM Sibylle Stöckli via R-help <
> r-help using r-project.org> wrote:
>
>> Dear community
>>
>> To import multiple .dat  weather files I am using list.files().
>> I intend to use the R package “ClimInd” to calculate different
>> agroclimatic indicators.
>>
>> Question: Is there another solution to import multiple .dat files so that
>> I can select elements from the list, e.g. one specific weather file
>> (example AAR_DailyWeather)?
>>
>>
>> # Import multiple .dat files weather data
>> filelist <- list.files(path =
>> "O:/Data-Work/……./Daten_RA-MeteoCH_1990-2021", pattern='*.dat', all.files=
>> T, full.names= T)
>> W <- lapply(filelist, function(x) read.table(x, header = TRUE, sep = "",
>> colClasses = "numeric", comment.char = ""))
>> W[[1]]
>>
>> > dd(data = W[[1]]$Precip, time.scale = W[[1]]$year)
>> Fehler in W[[1]]$year : $ operator is invalid for atomic vectors
>>
>> Kind regards
>> Sibylle
>>
>>
>>
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>

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