read.fwf
Read Fixed Width Format Files
Read a table of fixed width formatted
data into a data.frame.
- Keywords
- file, connection
Usage
read.fwf(file, widths, header = FALSE, sep = "\t", skip = 0, row.names, col.names, n = -1, buffersize = 2000, ...)Arguments
- file
-
the name of the file which the data are to be read from.
Alternatively,
filecan be a connection, which will be opened if necessary, and if so closed at the end of the function call. - widths
- integer vector, giving the widths of the fixed-width fields (of one line), or list of integer vectors giving widths for multiline records.
- header
- a logical value indicating whether the file contains the
names of the variables as its first line. If present, the names
must be delimited by
sep. - sep
- character; the separator used internally; should be a character that does not occur in the file (except in the header).
- skip
- number of initial lines to skip; see
read.table. - row.names
- see
read.table. - col.names
- see
read.table. - n
- the maximum number of records (lines) to be read, defaulting to no limit.
- buffersize
- Maximum number of lines to read at one time
- ...
- further arguments to be passed to
read.table. Useful such arguments includeas.is,na.strings,colClassesandstrip.white.
Details
Multiline records are concatenated to a single line before processing.
Fields that are of zero-width or are wholly beyond the end of the line
in file are replaced by NA.
Negative-width fields are used to indicate columns to be skipped, e.g.,
-5 to skip 5 columns. These fields are not seen by
read.table and so should not be included in a col.names
or colClasses argument (nor in the header line, if present).
Reducing the buffersize argument may reduce memory use when
reading large files with long lines. Increasing buffersize may
result in faster processing when enough memory is available.
Note that read.fwf (not read.table) reads the supplied
file, so the latter's arguments such as encoding and
fileEncoding will not be useful.
Value
-
A
data.frame as produced by read.table
which is called internally.
See Also
scan and read.table.
read.fortran for another style of fixed-format files.
Examples
library(utils)
ff <- tempfile()
cat(file = ff, "123456", "987654", sep = "\n")
read.fwf(ff, widths = c(1,2,3)) #> 1 23 456 \ 9 87 654
read.fwf(ff, widths = c(1,-2,3)) #> 1 456 \ 9 654
unlink(ff)
cat(file = ff, "123", "987654", sep = "\n")
read.fwf(ff, widths = c(1,0, 2,3)) #> 1 NA 23 NA \ 9 NA 87 654
unlink(ff)
cat(file = ff, "123456", "987654", sep = "\n")
read.fwf(ff, widths = list(c(1,0, 2,3), c(2,2,2))) #> 1 NA 23 456 98 76 54
unlink(ff)