foreign (version 0.8-47)

read.dbf: Read a DBF File

Description

The function reads a DBF file into a data frame, converting character fields to factors, and trying to respect NULL fields.

Usage

read.dbf(file, as.is = FALSE)

Arguments

file

name of input file

as.is

should character vectors not be converted to factors?

Value

• A data frame of data from the DBF file; note that the field names are adjusted to use in R using make.names(unique=TRUE).

  There is an attribute "data_type" giving the single-character dBase types for each field.

Details

DBF is the extension used for files written for the XBASE family of database languages, covering the dBase, Clipper, FoxPro, and their Windows equivalents Visual dBase, Visual Objects, and Visual FoxPro, plus some older products (http://www.clicketyclick.dk/databases/xbase/format/). Most of these follow the file structure used by Ashton-Tate's dBase II, III or 4 (later owned by Borland).

read.dbf is based on C code from http://shapelib.maptools.org/ which implements the XBASE specification. It can convert fields of type "L" (logical), "N" and "F" (numeric and float) and "D" (dates): all other field types are read as-is as character vectors. A numeric field is read as an Rinteger vector if it is encoded to have no decimals, otherwise as a numeric vector. However, if the numbers are too large to fit into an integer vector, it is changed to numeric. Note that is possible to read integers that cannot be represented exactly even as doubles: this sometimes occurs if IDs are incorrectly coded as numeric.

References

http://shapelib.maptools.org/.

The Borland file specification via http://www.wotsit.org, currently at http://www.wotsit.org/list.asp?fc=6.

See Also

write.dbf

Examples

x <- read.dbf(system.file("files/sids.dbf", package="foreign")[1])
str(x)
summary(x)