R: Write a data frame to a delimited file

write_delim {readr}

R Documentation

Write a data frame to a delimited file

Description

This is about twice as fast as write.csv(), and never writes row names. output_column() is a generic method used to coerce columns to suitable output.

Usage

write_delim(x, path, delim = " ", na = "NA", append = FALSE,
  col_names = !append)

write_csv(x, path, na = "NA", append = FALSE, col_names = !append)

write_excel_csv(x, path, na = "NA", append = FALSE, col_names = !append)

write_tsv(x, path, na = "NA", append = FALSE, col_names = !append)

Arguments

`x`	A data frame to write to disk
`path`	Path or connection to write to.
`delim`	Delimiter used to separate values. Defaults to `" "`. Must be a single character.
`na`	String used for missing values. Defaults to NA. Missing values will never be quoted; strings with the same value as `na` will always be quoted.
`append`	If `FALSE`, will overwrite existing file. If `TRUE`, will append to existing file. In both cases, if file does not exist a new file is created.
`col_names`	Write columns names at the top of the file?

Value

write_*() returns the input x invisibly.

Output

Factors are coerced to character. Doubles are formatted using the grisu3 algorithm. POSIXct's are formatted as ISO8601.

All columns are encoded as UTF-8. write_excel_csv() also includes a UTF-8 Byte order mark which indicates to Excel the csv is UTF-8 encoded.

Values are only quoted if needed: if they contain a comma, quote or newline.

References

Florian Loitsch, Printing Floating-Point Numbers Quickly and Accurately with Integers, PLDI '10, http://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf

Examples

tmp <- tempfile()
write_csv(mtcars, tmp)
head(read_csv(tmp))

# format_* is useful for testing and reprexes
cat(format_csv(head(mtcars)))
cat(format_tsv(head(mtcars)))
cat(format_delim(head(mtcars), ";"))

df <- data.frame(x = c(1, 2, NA))
format_csv(df, na = ".")

# Quotes are automatically as needed
df <- data.frame(x = c("a", '"', ",", "\n"))
cat(format_csv(df))

# A output connection will be automatically created for output filenames
# with appropriate extensions.
dir <- tempdir()
write_tsv(mtcars, file.path(dir, "mtcars.tsv.gz"))
write_tsv(mtcars, file.path(dir, "mtcars.tsv.bz2"))
write_tsv(mtcars, file.path(dir, "mtcars.tsv.xz"))

[Package readr version 1.1.0 Index]