read.table {base} | R Documentation |
Reads a file in table format and creates a data frame from it, with cases corresponding to lines and variables to fields in the file.
read.table(file, header = FALSE, sep = "", quote = "\"'", dec = ".", row.names, col.names, as.is = FALSE, na.strings = "NA", skip = 0, check.names = TRUE, fill = FALSE, strip.white = FALSE, blank.lines.skip = TRUE) read.csv(file, header = TRUE, sep = ",", quote="\"", dec=".", fill = TRUE, ...) read.csv2(file, header = TRUE, sep = ";", quote="\"", dec=",", fill = TRUE, ...) read.delim(file, header = TRUE, sep = "\t", quote="\"", dec=".", fill = TRUE, ...) read.delim2(file, header = TRUE, sep = "\t", quote="\"", dec=",", fill = TRUE, ...)
file |
the name of the file which the data are to be read from.
Each row of the table appears as one line of the file. If it does
not contain an absolute path, the file name is
relative to the current working directory,
getwd() .
Alternatively, file can be a connection , which
will be opened if necessary, and if so closed at the end of the
function call. However, since the file must be read twice, this
will be resource-intensive except on seekable connections.
|
header |
a logical value indicating whether the file contains the
names of the variables as its first line. If missing, the value is
determined from the file format: header is set to TRUE
if and only if the first row contains one fewer field than the
second. |
sep |
the field separator character. Values on each line of the
file are separated by this character. If sep = "" the
separator is ``white space'', that is one or more spaces, tabs or
newlines. |
quote |
the set of quoting characters. To disable quoting
altogether, use quote="" . See scan for the
behaviour on quotes embedded in quotes. |
dec |
the character used in the file for decimal points. |
row.names |
a vector of row names. This can be a vector giving the actual row names, or a single number giving the column of the table which contains the row names, or character string giving the name of the table column containing the row names. |
col.names |
a vector of optional names for the variables.
The default is to use "V" followed by the column number. |
as.is |
the default behavior of read.table is to convert
non-numeric variables to factors. The variable as.is
controls this conversion. Its value is either a vector of logicals
(values are recycled if necessary), or a vector of numeric indices
which specify which columns should be left as character strings. |
na.strings |
a vector strings which are to be interpreted as
NA values. |
skip |
the number of lines of the data file to skip before beginning to read data. |
check.names |
logical. If TRUE then the names of the
variables in the data frame are checked to ensure that they are
syntactically valid variable names. If necessary they are adjusted
(by make.names ) so that they are. |
fill |
logical. If TRUE then in case the rows have unequal
length, blank fields are implicitly added. |
strip.white |
logical. Used only when sep has
been specified, and allows the stripping of leading and trailing
white space from character fields (numeric fields
are always stripped). See scan for further details,
remembering that the columns may include the row names. |
blank.lines.skip |
logical: if TRUE blank lines in the
input are ignored. |
... |
Further arguments to read.table . |
If row.names
is not specified and the header line has one less
entry than the number of columns, the first column is taken to be the
row names. This allows data frames to be read in from the format in
which they are printed.
read.csv
and read.csv2
are identical to
read.table
except for the defaults. They are intended for
reading ``comma separated value'' files (`.csv') or the variant
used in countries that use a comma as decimal point and a semicolon
as field separator. Similarly, read.delim
and
read.delim2
are for reading delimited files, defaulting to the
TAB character for the delimiter. Notice that header = TRUE
and
fill = TRUE
in these variants.
A data frame (data.frame
) containing a representation of
the data in the file.
This function is the principal means of reading tabular data into R.
The implementation of read.table
currently reads everything as
character using scan
and subsequently defines
"numeric"
or factor
variables.
This is quite memory consuming for files of thousands of records and
may need larger memory, see Memory
.
The `R Data Import/Export' manual.
scan
,
read.fwf
for reading fixed width
formatted input;
read.table.url
for ``reading'' data from the internet;
write.table
;
data.frame
.