scan

R Base 3.6.2 🇮🇩 Bahasa Indonesia

Membaca data ke dalam vektor atau daftar dari konsol atau file.

Syntax

scan(file = "", what = double(), nmax = -1, n = -1, sep = "",
     quote = if(identical(sep, "\n")) "" else "'\"", dec = ".",
     skip = 0, nlines = 0, na.strings = "NA",
     flush = FALSE, fill = FALSE, strip.white = FALSE,
     quiet = FALSE, blank.lines.skip = TRUE, multi.line = TRUE,
     comment.char = "", allowEscapes = FALSE,
     fileEncoding = "", encoding = "unknown", text, skipNul = FALSE)

Arguments

Parameter	Deskripsi
`file`	the name of a file to read data values from. If the specified file is "", then input is taken from the keyboard (or whatever stdin() reads if input is redirected or R is embedded). (In this case input can be terminated by a blank line or an EOF signal, Ctrl-D on Unix and Ctrl-Z on Windows.) Otherwise, the file name is interpreted relative to the current working directory (given by getwd()), unless it specifies an absolute path. Tilde-expansion is performed where supported. When running R from a script, file = "stdin" can be used to refer to the process's stdin file stream. This can be a compressed file (see file). Alternatively, file can be a connection, which will be opened if necessary, and if so closed at the end of the function call. Whatever mode the connection is opened in, any of LF, CRLF or CR will be accepted as the EOL marker for a line and so will match sep = "\n". file can also be a complete URL. (For the supported URL schemes, see the ‘URLs’ section of the help for url.) To read a data file not in the current encoding (for example a Latin-1 file in a UTF-8 locale or conversely) use a file connection setting its encoding argument (or scan's fileEncoding argument).
`what`	the type of what gives the type of data to be read. (Here ‘type’ is used in the sense of typeof.) The supported types are logical, integer, numeric, complex, character, raw and list. If what is a list, it is assumed that the lines of the data file are records each containing length(what) items (‘fields’) and the list components should have elements which are one of the first six (atomic) types listed or NULL, see section ‘Details’ below.
`nmax`	the maximum number of data values to be read, or if what is a list, the maximum number of records to be read. If omitted or not positive or an invalid value for an integer (and nlines is not set to a positive value), scan will read to the end of file.
`n`	integer: the maximum number of data values to be read, defaulting to no limit. Invalid values will be ignored.
`sep`	by default, scan expects to read ‘white-space’ delimited input fields. Alternatively, sep can be used to specify a character which delimits fields. A field is always delimited by an end-of-line marker unless it is quoted. If specified this should be the empty character string (the default) or NULL or a character string containing just one single-byte character.
`quote`	the set of quoting characters as a single character string or NULL. In a multibyte locale the quoting characters must be ASCII (single-byte).
`dec`	decimal point character. This should be a character string containing just one single-byte character. (NULL and a zero-length character vector are also accepted, and taken as the default.)
`skip`	the number of lines of the input file to skip before beginning to read data values.
`nlines`	if positive, the maximum number of lines of data to be read.
`na.strings`	character vector. Elements of this vector are to be interpreted as missing (NA) values. Blank fields are also considered to be missing values in logical, integer, numeric and complex fields. Note that the test happens after white space is stripped from the input, so na.strings values may need their own white space stripped in advance.
`flush`	logical: if TRUE, scan will flush to the end of the line after reading the last of the fields requested. This allows putting comments after the last field, but precludes putting more that one record on a line.
`fill`	logical: if TRUE, scan will implicitly add empty fields to any lines with fewer fields than implied by what.
`strip.white`	vector of logical value(s) corresponding to items in the what argument. It is 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). Note: white space inside quoted strings is not stripped. If strip.white is of length 1, it applies to all fields; otherwise, if strip.white[i] is TRUE and the i-th field is of mode character (because what[i] is) then the leading and trailing unquoted white space from field i is stripped.
`quiet`	logical: if FALSE (default), scan() will print a line, saying how many items have been read.
`blank.lines.skip`	logical: if TRUE blank lines in the input are ignored, except when counting skip and nlines.
`multi.line`	logical. Only used if what is a list. If FALSE, all of a record must appear on one line (but more than one record can appear on a single line). Note that using fill = TRUE implies that a record will be terminated at the end of a line.
`comment.char`	character: a character vector of length one containing a single character or an empty string. Use "" to turn off the interpretation of comments altogether (the default).
`allowEscapes`	logical. Should C-style escapes such as \n be processed (the default) or read verbatim? Note that if not within quotes these could be interpreted as a delimiter (but not as a comment character). The escapes which are interpreted are the control characters \a, \b, \f, \n, \r, \t, \v and octal and hexadecimal representations like \040 and \0x2A. Any other escaped character is treated as itself, including backslash. Note that Unicode escapes (starting \u or \U: see Quotes) are never processed.
`fileEncoding`	character string: if non-empty declares the encoding used on a file (not a connection nor the keyboard) so the character data can be re-encoded. See the ‘Encoding’ section of the help for file, and the ‘R Data Import/Export Manual’.
`encoding`	encoding to be assumed for input strings. If the value is "latin1" or "UTF-8" it is used to mark character strings as known to be in Latin-1 or UTF-8: it is not used to re-encode the input (see fileEncoding). See also ‘Details’.
`text`	character string: if file is not supplied and this is, then data are read from the value of text via a text connection.
`skipNul`	logical: should nuls be skipped when reading character fields?

Return Value

jika apa itu daftar, daftar yang panjangnya sama dan nama yang sama (seperti apa pun) dengan apa. Jika tidak, vektor bertipe apa. String karakter dalam hasil akan dideklarasikan pengkodeannya jika pengkodeannya adalah "latin1" atau "UTF-8".

Details

Nilai dari apa yang dapat berupa daftar tipe, dalam hal ini scan mengembalikan daftar vektor dengan tipe yang diberikan oleh tipe elemen di dalamnya. Ini menyediakan cara membaca data kolom. Jika salah satu tipenya adalah NULL, bidang terkait akan dilewati (tetapi komponen NULL muncul di hasilnya). Tipe apa atau komponennya dapat berupa salah satu dari enam tipe vektor atom atau NULL (lihat is.atomic). 'Spasi putih' didefinisikan untuk keperluan fungsi ini sebagai satu atau lebih karakter yang berdekatan dari spasi yang ditetapkan, tab horizontal, kembalinya pengangkutan, dan umpan baris. Itu tidak termasuk umpan formulir atau tab vertikal, tetapi di lokal Latin-1 dan Windows 8-bit (tetapi bukan UTF-8) 'spasi' menyertakan spasi "\xa0" yang tidak dapat terputus. Bidang numerik yang kosong selalu dianggap sebagai nilai yang hilang. Bidang karakter kosong

Contoh

Example

# NOT RUN {
cat("TITLE extra line", "2 3 5 7", "11 13 17", file = "ex.data", sep = "\n")
pp <- scan("ex.data", skip = 1, quiet = TRUE)
scan("ex.data", skip = 1)
scan("ex.data", skip = 1, nlines = 1) # only 1 line after the skipped one
scan("ex.data", what = list("","","")) # flush is F -> read "7"
scan("ex.data", what = list("","",""), flush = TRUE)
unlink("ex.data") # tidy up

## "inline" usage
scan(text = "1 2 3")

# }