Reading in a large number of dbf files
Steve
If the .dbf extension files are dBase type.
generalizing: there are 2 series of dbase .dbf files for non SQL type dbf
files:
1 dBase III when Borland had dBase and
2 dBase 2000 produced by dBase inc
If they are dbase III (ie can be imported into Excel) you can use the
foreign package to import them
require(foreign)
# get a list of files
listd <- list.files(.....)
# loop or otherwise
for (j in seq_along(lisd) ) {
# Example for 1 file (you will have to use something different for > 1)
x <- read.dbf(list[j], as.is = TRUE)
}
Regards
Duncan Mackay
Department of Agronomy and Soil Science
University of New England
ARMIDALE NSW 2351
Email home: mackay at northnet.com.au
At 00:35 17/04/2009, you wrote:
good morning
This question is not a stats question per say but a data management and
lattice plotting problem. I apologize now if I'm asking an inappropriate
question to this gracious group.
I'm need to bring in approximately 100 *.dbf files into R but I'm having
difficultly understanding several examples I've tracked down regarding this
procedure and could benefit from your suggestions.
One example I've found does the following:
DF <- lappy(dir(pattern="file.*\\.txt"), read.table, sep=";". header= TRUE)
names(DF) <- paste("data", seq_along(DF), sep = "")
This solution will not work for me for at least 2 reasons:
1) I need to modify the files after I import them by adding three new
parameters to each file prior to combining them into a common data.frame
For example one of my files is called SRF_DryDry_stats.dbf. The name of
the file tells me that it refers to two conditions; 1) SRF = an indictor
region field, and 2) DryDry = dry hydrological conditions. I also know that
the data refer to a particular species.
The data in the file include some general summarizing statistics (Min,
Max, Range, Mean, and STD). After modifying the file, I need a species
field, the SRF field and the hydro condition parameters in the file. After
this modification, I need to "cbind" these files into a common file.
2) The goal is to use the common file to produce a series of lattice
barchart graphs using the three new parameters as factors and plotting the
some of the statistics in the lattice call statements.
Is there a clean way of accomplishing these tasks or should the brute force
approach be taken?
Steve Friedman Ph. D.
Spatial Statistical Analyst
Everglades and Dry Tortugas National Park
950 N Krome Ave (3rd Floor)
Homestead, Florida 33034
Steve_Friedman at nps.gov
Office (305) 224 - 4282
Fax (305) 224 - 4147
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