Usage
ReadData(con, headers = c(FALSE, FALSE, FALSE), sep = "",
quote = ""'", nrows = -1, na.strings = c("", "NA"),
skip = 0, comment.char = "#", encoding = getOption("encoding"))
- con
{connection; a connection object.}
- headers
{logical; a vector of length 3 that indicates whether the
data table contains header lines: see Details.}
- sep
{character; the field separator string. Values on each line of the
file are separated by this string.}
- quote
{character; the set of quoting characters.}
- nrows
{integer; the maximum number of rows to read in. Negative and other
invalid values are ignored (optional).}
- na.strings
{character; a vector of strings which are interpreted as
NA values. Blank fields are also considered to be missing
values.}
- skip
{integer; the number of lines to skip before beginning to read data.}
- comment.char
{character; a vector of length one containing a single
character or an empty string. Use "" to turn off the interpretation of
comments altogether.}
- encoding
{character; encoding to be assumed for input strings. If the
value is "latin1" or "UTF-8" it is used to mark character
strings as known to be in Latin-1 or UTF-8: it is not used to re-encode the
input.}
The imported data table requires at least two numeric variables.
This function is the primary method for importing table formatted data from
a text file. The headers argument, a logical vector of length 3,
indicates whether the file contains the names, measurement units, and conversion
specification formats of the variables as its initial lines. For example,
headers = c(TRUE, FALSE, TRUE) indicates that the first and second
lines contain the names and formats of variables, respectively; with
measurement units excluded. If headers = c(FALSE, FALSE, FALSE),
the default, no header information is contained within the file.
Formats are the character representation of object types
used to: identify column classes prior to reading in data,
and format values for printing.
Conversion specifications are based on C-style string formatting
commands for numeric, integer, and character
object classes, see sprintf; for example,
a format string of "%.5f" applied to the mathematical constant pi
results in "3.14159". Calendar date and time objects of class POSIXct are
defined by the ISO C99 / POSIX standard, see strftime;
for example, "02/26/2010 02:05:39 PM" is represented using
"%d/%m/%Y %I:%M:%S %p".
Performance issues associated with reading in large files can be alleviated
by specifying formats in a header line, and giving the maximum number of
rows to read in.
Returns a list with the following components:
- dat
{data.frame; a data table with headers and comments removed.}
- cols
{list; length equal to the current number of data variables.
Each component in cols is linked to a specific variable,
see ManageData.}
- vars
{list; an initial guess of the state variables. Integer components
x, y, z, and t specify the index number in
cols that correspond to the respective state variable.}
[object Object]
read.table
f <- system.file("extdata/DataExample.txt", package = "RSurvey")
con <- file(f, open = "r", encoding = "latin1")
ans <- ReadData(con, headers = c(TRUE, TRUE, TRUE))
close(con)
file