write.table prints its required argument
x (after converting it to a data frame if it is not one nor a matrix) to a file or connection.
write.table(x, file = "", append = FALSE, quote = TRUE, sep = " ", eol = "\n", na = "NA", dec = ".", row.names = TRUE, col.names = TRUE, qmethod = c("escape", "double"), fileEncoding = "") write.csv(...) write.csv2(...)
- the object to be written, preferably a matrix or data frame. If not, it is attempted to coerce
xto a data frame.
- either a character string naming a file or a connection open for writing.
""indicates output to the console.
- logical. Only relevant if
fileis a character string. If
TRUE, the output is appended to the file. If
FALSE, any existing file of the name is destroyed.
- a logical value (
FALSE) or a numeric vector. If
TRUE, any character or factor columns will be surrounded by double quotes. If a numeric vector, its elements are taken as the indices of columns to quote. In both cases, row and column names are quoted if they are written. If
FALSE, nothing is quoted.
- the field separator string. Values within each row of
xare separated by this string.
- the character(s) to print at the end of each line (row). For example,
eol = "\r\n"will produce Windows' line endings on a Unix-alike OS, and
eol = "\r"will produce files as expected by Excel:mac 2004.
- the string to use for missing values in the data.
- the string to use for decimal points in numeric or complex columns: must be a single character.
- either a logical value indicating whether the row names of
xare to be written along with
x, or a character vector of row names to be written.
- either a logical value indicating whether the column names of
xare to be written along with
x, or a character vector of column names to be written. See the section on ‘CSV files’ for the meaning of
col.names = NA.
- a character string specifying how to deal with embedded double quote characters when quoting strings. Must be one of
write.table), in which case the quote character is escaped in C style by a backslash, or
write.csv2), in which case it is doubled. You can specify just the initial letter.
- character string: if non-empty declares the encoding to be used on a file (not a connection) so the character data can be re-encoded as they are written. See
- arguments to
qmethodcannot be altered.
If the table has no columns the rownames will be written only if
row.names = TRUE, and vice versa.
Real and complex numbers are written to the maximal possible precision.
If a data frame has matrix-like columns these will be converted to multiple columns in the result (via
as.matrix) and so a character
col.names or a numeric
quote should refer to the columns in the result, not the input. Such matrix-like columns are unquoted by default.
Any columns in a data frame which are lists or have a class (e.g. dates) will be converted by the appropriate
as.character method: such columns are unquoted by default. On the other hand, any class information for a matrix is discarded and non-atomic (e.g. list) matrices are coerced to character.
Only columns which have been converted to character will be quoted if specified by
dec argument only applies to columns that are not subject to conversion to character because they have a class or are part of a matrix-like column (or matrix), in particular to columns protected by
options("OutDec") to control such conversions.
In almost all cases the conversion of numeric quantities is governed by the option
options), but with the internal equivalent of
digits = 15. For finer control, use
format to make a character matrix/data frame, and call
write.table on that.
These functions check for a user interrupt every 1000 lines of output.
By default there is no column name for a column of row names. If
col.names = NA and
row.names = TRUE a blank column name is added, which is the convention used for CSV files to be read by spreadsheets. Note that such CSV files can be read in R by
read.csv(file = "
", row.names = 1)
write.csv2 provide convenience wrappers for writing CSV files. They set
dec (see below),
qmethod = "double", and
row.names = TRUE (the default) and to
"." for the decimal point and a comma for the separator.
write.csv2 uses a comma for the decimal point and a semicolon for the separator, the Excel convention for CSV files in some Western European locales.
These wrappers are deliberately inflexible: they are designed to ensure that the correct conventions are used to write a valid file. Attempts to change
qmethod are ignored, with a warning. CSV files do not record an encoding, and this causes problems if they are not ASCII for many other applications. Windows Excel 2007/10 will open files (e.g. by the file association mechanism) correctly if they are ASCII or UTF-16 (use
fileEncoding = "UTF-16LE") or perhaps in the current Windows codepage (e.g.
"CP1252"), but the ‘Text Import Wizard’ (from the ‘Data’ tab) allows far more choice of encodings. Excel:mac 2004/8 can import only Macintosh (which seems to mean MacRoman), Windows (perhaps Latin-1) and ‘PC-8’ files. OpenOffice 3.x asks for the character set when opening the file.
There is an IETF RFC4180 (http://tools.ietf.org/html/rfc4180) for CSV files, which mandates comma as the separator and CRLF line endings.
write.csv writes compliant files on Windows: use
eol = "\r\n" on other platforms.
write.table can be slow for data frames with large numbers (hundreds or more) of columns: this is inevitable as each column could be of a different class and so must be handled separately. If they are all of the same class, consider using a matrix instead.
## Not run: ## To write a CSV file for input to Excel one might use x <- data.frame(a = I("a " quote"), b = pi) write.table(x, file = "foo.csv", sep = ",", col.names = NA, qmethod = "double") ## and to read this file back into R one needs read.table("foo.csv", header = TRUE, sep = ",", row.names = 1) ## NB: you do need to specify a separator if qmethod = "double". ### Alternatively write.csv(x, file = "foo.csv") read.csv("foo.csv", row.names = 1) ## or without row names write.csv(x, file = "foo.csv", row.names = FALSE) read.csv("foo.csv") ## To write a file in MacRoman for simple use in Mac Excel 2004/8 write.csv(x, file = "foo.csv", fileEncoding = "macroman") ## or for Windows Excel 2007/10 write.csv(x, file = "foo.csv", fileEncoding = "UTF-16LE") ## End(Not run)
Documentation reproduced from R 2.15.3. License: GPL-2.