Hello I have data from various Scottish river catchments in the form of
csv files. I want to be able to download the files in turn and refer to
each one by an assigned name from a vector of names, but within R. So, for
example, if my vector of names is
c("tay","forth","don") I want to tell R
to refer to the sequences of dataframes as a variable name, ie the table
uploaded from the first csv becomes the object tay *within* R and so on, so
that I could the do things like write print(tay[,1]) etc,rather than having
to refer to a list eg print(riverlist[[1]][,1]) I don't know whether this
is possible but if it is I'd be grateful for any pointers
Thanks, Nick Wray
[[alternative HTML version deleted]]
It's definitely possible to create R objects without knowing their names
using 'assign', but this is considered bad practice. For example,
assign("tay", riverlist[["tay"]])
And you could put that in a for loop, looping through the names of your
files.
You could consider using 'attach'. You would write something like
attach(riverlist) and it would assign your variables into a new environment
and put it on your search list. Only problem is that modifying these
objects will (generally) create new objects, and not modify the originals.
For example, tay[[1]] <- NA
will create a new variable tay in your global environment, and not modify
the variable in your
riverlist environment. Maybe that's how you want it to work, up to you.
In general though, I would say that making variables in either of these
manners is setting yourself up for failure. It is much better to do
tay <- read.csv(...)
forth <- read.csv(...)
...
One final solution is to do what you're currently doing, but use names to
refer to a data frame in a list, instead of integers.
For example, if your csv files are "tay.csv", "forth.csv",
and "don.csv",
and you had those strings stored in a variable 'riverfiles'
then remove the .csv and give the riverlist some names like
names(riverlist) <- sub("[.]csv$", "", riverfiles)
I hope this helps.
On Sun, Mar 20, 2022, 18:03 Nick Wray <nickmwray at gmail.com> wrote:
> Hello I have data from various Scottish river catchments in the form of
> csv files. I want to be able to download the files in turn and refer to
> each one by an assigned name from a vector of names, but within R. So, for
> example, if my vector of names is
c("tay","forth","don") I want to tell R
> to refer to the sequences of dataframes as a variable name, ie the table
> uploaded from the first csv becomes the object tay *within* R and so on, so
> that I could the do things like write print(tay[,1]) etc,rather than having
> to refer to a list eg print(riverlist[[1]][,1]) I don't know whether
this
> is possible but if it is I'd be grateful for any pointers
> Thanks, Nick Wray
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
[[alternative HTML version deleted]]
Unless you want to make some transformation like tay/don it might work better to
make a new variable with catchment and append one dataset to the other. If later
you decide that was a bad choice, use pivot_wider to reorganize the data.
Tim
-----Original Message-----
From: R-help <r-help-bounces at r-project.org> On Behalf Of Nick Wray
Sent: Sunday, March 20, 2022 6:03 PM
To: r-help at r-project.org
Subject: [R] Naming files within R code
[External Email]
Hello I have data from various Scottish river catchments in the form of
csv files. I want to be able to download the files in turn and refer to each
one by an assigned name from a vector of names, but within R. So, for example,
if my vector of names is c("tay","forth","don") I
want to tell R to refer to the sequences of dataframes as a variable name, ie
the table uploaded from the first csv becomes the object tay *within* R and so
on, so that I could the do things like write print(tay[,1]) etc,rather than
having to refer to a list eg print(riverlist[[1]][,1]) I don't know whether
this is possible but if it is I'd be grateful for any pointers Thanks, Nick
Wray
[[alternative HTML version deleted]]
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provide commented, minimal, self-contained, reproducible code.
Hello,
You can read in the files in a `lapply` loop, assign the result to a
list, say df_list, and
names(df_list) <- c("tay","forth","don")
list2env(df_list, envir = globalenv())
This creates 3 data.frames with those names in the global environment.
Hope this helps,
Rui Barradas
?s 22:02 de 20/03/2022, Nick Wray escreveu:> Hello I have data from various Scottish river catchments in the form of
> csv files. I want to be able to download the files in turn and refer to
> each one by an assigned name from a vector of names, but within R. So, for
> example, if my vector of names is
c("tay","forth","don") I want to tell R
> to refer to the sequences of dataframes as a variable name, ie the table
> uploaded from the first csv becomes the object tay *within* R and so on, so
> that I could the do things like write print(tay[,1]) etc,rather than having
> to refer to a list eg print(riverlist[[1]][,1]) I don't know whether
this
> is possible but if it is I'd be grateful for any pointers
> Thanks, Nick Wray
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.