?list files
... in particular the pattern argument
--
David Winsemius
On Feb 12, 2009, at 3:38 PM, Stropharia wrote:
Thanks a lot Levi. Your code was much shorter and more elegant. With
a few
minor alterations I got this (see below) to work.
Does anyone know if there is a way to automate getting only the csv
filenames in a folder (rather than the whole file path)? Or to
automate
extracting the file names from the file paths, once they have been
extracted
using Sys-glob? Thanks.
Steve
# ----------------------------------------START
R-CODE-----------------------------------
filenames <- Sys.glob("/Users/Desktop/Test/*.csv") # get names of
files to
process # use * to get all
variables <- data.frame(1:length(filenames)) # preallocate assuming
multiple
values from each file # creates a dataframe with the same length of
rows as
the number of .csv files to process
docalc <- function(filenames){
input <- read.csv(filenames, header=TRUE, na.strings="NA")
attach(input)
result.A <- x[2]*y[1]
result.B <- y[2]-x[1]
result.C <- x[3]+y[1]
results <- c(result.A, result.B, result.C) # concatenate result
vectors
names(results) <- c("ResultA", "ResultB", "ResultC") # set names
for
result vectors
return(results)
}
variables <- t(sapply(filenames, docalc)) # transpose and sapply
filenames
# export to csv file
write.csv(variables, file="/Users/Desktop/Test.csv")
# ----------------------------------------END
R-CODE-----------------------------------
Levi Waldron-3 wrote:
Stropharia wrote:
# ----------------------------------------START
R-CODE-----------------------------------
filenames <- Sys.glob("/Users/Desktop/Test/*.csv") # get names of
files
to
process # use * to get all
variables <- data.frame(1:length(filenames)) # preallocate assuming
multiple
values from each file # creates a dataframe with the same length
of rows
as
the number of .csv files to process
for (i in seq_along(filenames)){
input <- read.csv(filenames[i], header=TRUE, na.strings="NA")
data.frame("input")
attach(input)
result.A <- x[2]*y[1]
result.B <- y[2]-x[1]
result.C <- x[3]+y[1]
results <- c(result.A, result.B, result.C) # concatenate result
vectors
variables[i] <- results
}
variables <- as.data.frame(t(as.matrix(variables))) # turn result
vectors
into a matrix, then transpose it and output as a data frame
# add column and row names
c.names <- c("ResultA", "ResultB", "ResultC") # set names for result
vectors
colnames(variables) <- c.names
rownames(variables) <- filenames
# export to csv file
write.csv(variables, file="/Users/Desktop/Test.csv")
# ----------------------------------------END
R-CODE-----------------------------------
I think something like this should work better:
docalc <- function(thisfile){
input <- read.csv(filenames[i], header=TRUE, na.strings="NA")
attach(input)
result.A <- x[2]*y[1]
result.B <- y[2]-x[1]
result.C <- x[3]+y[1]
results <- c(result.A, result.B, result.C) # concatenate result
vectors
names(results) <- c("ResultA", "ResultB", "ResultC")
return(results)
}
variables <- sapply(filenames,docalc)
--
Levi Waldron
post-doctoral fellow
Jurisica Lab, Ontario Cancer Institute
Division of Signaling Biology
IBM Life Sciences Discovery Centre
TMDT 9-304D
101 College Street
Toronto, Ontario M5G 1L7
(416)581-7453
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______________________________________________
R-help@r-project.org mailing list
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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.
______________________________________________
R-help@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.
