readr: read_lines – R documentation

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read_lines

Read/write lines to/from a file

Description

read_lines() reads up to n_max lines from a file. New lines are not included in the output. read_lines_raw() produces a list of raw vectors, and is useful for handling data with unknown encoding. write_lines() takes a character vector or list of raw vectors, appending a new line after each entry.

Usage

read_lines(
  file,
  skip = 0,
  skip_empty_rows = FALSE,
  n_max = -1L,
  locale = default_locale(),
  na = character(),
  progress = show_progress()
)

read_lines_raw(file, skip = 0, n_max = -1L, progress = show_progress())

write_lines(
  x,
  file,
  sep = "\n",
  na = "NA",
  append = FALSE,
  path = deprecated()
)

Arguments

`file`	Either a path to a file, a connection, or literal data (either a single string or a raw vector). Files ending in `.gz`, `.bz2`, `.xz`, or `.zip` will be automatically uncompressed. Files starting with `http://`, `https://`, `ftp://`, or `ftps://` will be automatically downloaded. Remote gz files can also be automatically downloaded and decompressed. Literal data is most useful for examples and tests. It must contain at least one new line to be recognised as data (instead of a path) or be a vector of greater than length 1. Using a value of `clipboard()` will read from the system clipboard.
`skip`	Number of lines to skip before reading data.
`skip_empty_rows`	Should blank rows be ignored altogether? i.e. If this option is `TRUE` then blank rows will not be represented at all. If it is `FALSE` then they will be represented by `NA` values in all the columns.
`n_max`	Number of lines to read. If `n_max` is -1, all lines in file will be read.
`locale`	The locale controls defaults that vary from place to place. The default locale is US-centric (like R), but you can use `locale()` to create your own locale that controls things like the default time zone, encoding, decimal mark, big mark, and day/month names.
`na`	Character vector of strings to interpret as missing values. Set this option to `character()` to indicate no missing values.
`progress`	Display a progress bar? By default it will only display in an interactive session and not while knitting a document. The display is updated every 50,000 values and will only display if estimated reading time is 5 seconds or more. The automatic progress bar can be disabled by setting option `readr.show_progress` to `FALSE`.
`x`	A character vector or list of raw vectors to write to disk.
`sep`	The line separator. Defaults to `\\n`, commonly used on POSIX systems like macOS and linux. For native windows (CRLF) separators use `\\r\\n`.
`append`	If `FALSE`, will overwrite existing file. If `TRUE`, will append to existing file. In both cases, if the file does not exist a new file is created.
`path`

Value

read_lines(): A character vector with one element for each line. read_lines_raw(): A list containing a raw vector for each line.

write_lines() returns x, invisibly.

Examples

read_lines(file.path(R.home("doc"), "AUTHORS"), n_max = 10)
read_lines_raw(file.path(R.home("doc"), "AUTHORS"), n_max = 10)

tmp <- tempfile()

write_lines(rownames(mtcars), tmp)
read_lines(tmp)
read_file(tmp) # note trailing \n

write_lines(airquality$Ozone, tmp, na = "-1")
read_lines(tmp)

readr

Read Rectangular Text Data

v1.4.0

GPL (>= 2) | file LICENSE

Authors

Hadley Wickham [aut], Jim Hester [aut, cre], Romain Francois [ctb], R Core Team [ctb] (Date time code adapted from R), RStudio [cph, fnd], Jukka Jylänki [ctb, cph] (grisu3 implementation), Mikkel Jørgensen [ctb, cph] (grisu3 implementation)

Initial release