R: Data Output

write.table {base}

R Documentation

Data Output

Description

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.

Usage

write.table(x, file = "", append = FALSE, quote = TRUE, sep = " ",
            eol = "\n", na = "NA", dec = ".", row.names = TRUE,
	    col.names = TRUE, qmethod = c("escape", "double"))

write.csv(..., col.names = NA, sep = ",", qmethod = "double")
write.csv2(..., col.names = NA, dec = ",", sep = ";", qmethod = "double")

Arguments

x

the object to be written, preferably a matrix or data frame. If not, it is attempted to coerce x to a data frame.

file

either a character string naming a file or a connection. "" indicates output to the console.

append

logical. If TRUE, the output is appended to the file. If FALSE, any existing file of the name is destroyed.

quote

a logical value 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 the columns to quote. In both cases, row and column names are quoted if they are written. If FALSE, nothing is quoted.

sep

the field separator string. Values within each row of x are separated by this string.

eol

the character(s) to print at the end of each line (row).

na

the string to use for missing values in the data.

dec

the string to use for decimal points in numeric or complex columns: must be a single character.

row.names

either a logical value indicating whether the row names of x are to be written along with x, or a character vector of row names to be written.

col.names

either a logical value indicating whether the column names of x are to be written along with x, or a character vector of column names to be written.

qmethod

a character string specifying how to deal with embedded double quote characters when quoting strings. Must be one of "escape" (default), in which case the quote character is escaped in C style by a backslash, or "double", in which case it is doubled. You can specify just the initial letter.

...

further arguments to write.table.

Details

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. This can be used to write CSV files for input to spreadsheets. write.csv and write.csv2 provide convenience wrappers for doing so.

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.

The 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, in particular to columns protected by I().

Note

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.

Examples

## 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)

## End(Not run)

[Package base version 2.1.1 ]