On Wed, 6 Aug 2008, zack holden wrote:
Dear R wizards,
I have a folder containing 1000 files. For each file, I need to extract the
first row of each file, paste it to a new file, then write out that file. Then
I need to repeat this operation for each additional row (row 2, then row 3,
etc) for 23 rows in each file.
I can do this with a for loop (as below).
This is surprising!
Can you give us an example where this actually works???
Is there a way to use some of the indexing power of R to get around this nasty
loop?
Thank you in advance for any suggestions
###################
newoutfile <- data.frame()
list <- list.files("c:/data")
Bad practive to use 'list' as a variable name!
file = 1
Above seems superfluous in view of the next line
for(file in list) {
row <- file[1, ]
This doesn't really work, does it?
Where was dim(file) assigned?
newoutfile <- rbind(row, newoutfile)
Since 'newoutfile' was not intialized the above should have thrown an
error.
file = file + 1
Ought to have thrown an error like
"non-numeric argument to binary operator"
when trying to execute the line above.
write.csv(outfile, file = "output.csv")
}
####################
You were asked to:
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Chuck
p.s. As you describe the problem, something like this should do
res <- sapply( list.files("c:/data",full=TRUE), readLines )
for ( i in seq(nrow(res) ) ){
write.csv( res[i,],
file=paste("row",i,"csv",sep='.'))
}
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Charles C. Berry (858) 534-2098
Dept of Family/Preventive Medicine
E mailto:[EMAIL PROTECTED] UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
