Dear all,
I think I'm nearly there in writing R code which will read in files with two
variable parts to the file name and then assigning these file names to objects,
which also have two variable parts. I have got the code running without
encountering errors, however, I receive 50+ of the same warnings:
1: In assign(paste("Fekete_", index$year, index$month, sep =
""), ... :
only the first element is used as variable name
And it's true, when I do ls() only Fekete198601 has been assigned. I've
attempted to rectify this, but have only come up against further errors.
The code as it stands, is as follows:
# READ IN FILES FROM DISK
# File names have two variable parts: creating a 'file index' is a
two-step process
index <- expand.grid(year = sprintf("%04d", seq(1986, 1995)), month
= sprintf("%02d", 1:12))
filelist <- paste("C:\\Documents and
Settings\\Data\\comp_runoff_hd_", paste(index$year, index$month,
sep=''), '.asc', sep='')
filelist
# Assign file names to individual objects with variable name components
for (i in filelist) {
assign(paste("Fekete_",index$year, index$month,
sep=''),read.table(file=i, header=FALSE, sep=" "))
update <- substr(i,35,55) # substring - 2nd argument is character
at which extraction is to begin, 3rd argument is where extraction ends.
print(c("LOADED FILE:",update), quote=FALSE)
}
> ls()
[1] "Fekete_198601" "filelist" "i"
"index"
[5] "update"
Why is it that only Fekete_198601 has had data assigned to it (there should be
120 such objects in total) and how do I go about solving this?
Many thanks again for any help offered,
Steve
The variable name in your call to assign should vary within the for loop, otherwise you're always assigning the value to the same variable. Consider the following example,> listOfNames <- c("a", "b", "c") > listOfVariables <- c("vara", "varb", "varc") > > for(index in seq_along(listOfNames)){ > > print(index) # integer sweeping the two lists > print(paste("assigning variable", listOfNames[index], "to ", > listOfVariables[index])) > assign(listOfNames[index], listOfVariables[index]) > > } > > > # or more succinctly > mapply(assign, x=listOfNames, value=listOfVariables)HTH, baptiste On 27 Mar 2009, at 18:11, Steve Murray wrote:> > Dear all, > > I think I'm nearly there in writing R code which will read in files > with two variable parts to the file name and then assigning these > file names to objects, which also have two variable parts. I have > got the code running without encountering errors, however, I receive > 50+ of the same warnings: > > 1: In assign(paste("Fekete_", index$year, index$month, sep = > ""), ... : > only the first element is used as variable name > > And it's true, when I do ls() only Fekete198601 has been assigned. > I've attempted to rectify this, but have only come up against > further errors. > > The code as it stands, is as follows: > > > # READ IN FILES FROM DISK > > # File names have two variable parts: creating a 'file index' is a > two-step process > > index <- expand.grid(year = sprintf("%04d", seq(1986, 1995)), month > = sprintf("%02d", 1:12)) > filelist <- paste("C:\\Documents and Settings\\Data\ > \comp_runoff_hd_", paste(index$year, index$month, sep=''), '.asc', > sep='') > > filelist > > > # Assign file names to individual objects with variable name > components > > for (i in filelist) { > assign(paste("Fekete_",index$year, index$month, > sep=''),read.table(file=i, header=FALSE, sep=" ")) > > > update <- substr(i,35,55) # substring - 2nd argument is > character at which extraction is to begin, 3rd argument is where > extraction ends. > print(c("LOADED FILE:",update), quote=FALSE) > } > > >> ls() > [1] "Fekete_198601" "filelist" "i" "index" > [5] "update" > > > Why is it that only Fekete_198601 has had data assigned to it (there > should be 120 such objects in total) and how do I go about solving > this? > > > Many thanks again for any help offered, > > > Steve > > ______________________________________________ > R-help at r-project.org mailing list > 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._____________________________ Baptiste Augui? School of Physics University of Exeter Stocker Road, Exeter, Devon, EX4 4QL, UK Phone: +44 1392 264187 http://newton.ex.ac.uk/research/emag
Look at what
paste("Fekete_",index$year, index$month, sep='')
is creating in the 'assign'; it is a character vector that have the
same value each time through the loop. What you may want to do is
something like this:
index <- expand.grid(year = sprintf("%04d", seq(1986, 1995)), month
sprintf("%02d", 1:12))
# Assign file names to individual objects with variable name components
for (i in seq(nrow(index))) {
assign(paste("Fekete_",index$year[i], index$month[i],
sep=''),
read.table(file=paste("C:\\Documents and
Settings\\Data\\comp_runoff_hd_", index$year[i],
index$month[i], sep=""), header=FALSE, sep="
"))
update <- substr(i,35,55) # substring - 2nd argument is
character at which extraction is to begin, 3rd argument is where
extraction ends.
print(c("LOADED FILE:",update), quote=FALSE)
}
On Fri, Mar 27, 2009 at 2:11 PM, Steve Murray <smurray444 at hotmail.com>
wrote:>
> Dear all,
>
> I think I'm nearly there in writing R code which will read in files
with two variable parts to the file name and then assigning these file names to
objects, which also have two variable parts. I have got the code running without
encountering errors, however, I receive 50+ of the same warnings:
>
> 1: In assign(paste("Fekete_", index$year, index$month, sep =
""), ?... :
> ?only the first element is used as variable name
>
> And it's true, when I do ls() only Fekete198601 has been assigned.
I've attempted to rectify this, but have only come up against further
errors.
>
> The code as it stands, is as follows:
>
>
> # READ IN FILES FROM DISK
>
> # File names have two variable parts: creating a 'file index' is a
two-step process
>
> index <- expand.grid(year = sprintf("%04d", seq(1986, 1995)),
month = sprintf("%02d", 1:12))
> filelist <- paste("C:\\Documents and
Settings\\Data\\comp_runoff_hd_", paste(index$year, index$month,
sep=''), '.asc', sep='')
>
> filelist
>
>
> # Assign file names to individual objects with variable name components
>
> for (i in filelist) {
> ? ? ? ? ?assign(paste("Fekete_",index$year, index$month,
sep=''),read.table(file=i, header=FALSE, sep=" "))
>
>
> ? ? ? ? ?update <- substr(i,35,55) # substring - 2nd argument is
character at which extraction is to begin, 3rd argument is where extraction
ends.
> ? ? ? ? ?print(c("LOADED FILE:",update), quote=FALSE)
> ? ? ? ? ?}
>
>
>> ls()
> [1] "Fekete_198601" "filelist" ? ? ?"i" ? ? ?
? ? ? "index"
> [5] "update"
>
>
> Why is it that only Fekete_198601 has had data assigned to it (there should
be 120 such objects in total) and how do I go about solving this?
>
>
> Many thanks again for any help offered,
>
>
> Steve
>
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
>
--
Jim Holtman
Cincinnati, OH
+1 513 646 9390
What is the problem that you are trying to solve?