| print.default {base} | R Documentation |
Default Printing
Description
print.default is the default method of the generic
print function which prints its argument.
Usage
## Default S3 method:
print(x, digits = NULL, quote = TRUE,
na.print = NULL, print.gap = NULL, right = FALSE,
max = NULL, width = NULL, useSource = TRUE, ...)
Arguments
x |
the object to be printed. |
digits |
a non-null value for |
quote |
logical, indicating whether or not strings
( |
na.print |
a character string which is used to indicate
|
print.gap |
a non-negative integer |
right |
logical, indicating whether or not strings should be right aligned. The default is left alignment. |
max |
a non-null value for |
width |
controls the maximum number of columns on a line used in
printing vectors, matrices, etc. The default, |
useSource |
logical, indicating whether to use source references or copies rather than deparsing language objects. The default is to use the original source if it is available. |
... |
further arguments to be passed to or from other methods. They are ignored in this function. |
Details
The default for printing NAs is to print NA (without
quotes) unless this is a character NA and quote =
FALSE, when ‘<NA>’ is printed. When na.print is not NULL,
it handles how character NA is displayed, with no interaction with quote.
The same number of decimal places is used throughout a vector. This
means that digits specifies the minimum number of significant
digits to be used, and that at least one entry will be encoded with
that minimum number. However, if all the encoded elements then have
trailing zeroes, the number of decimal places is reduced until at
least one element has a non-zero final digit. Decimal points are only
included if at least one decimal place is selected.
You can suppress “exponential” / scientific notation in
printing of numbers (atomic vectors x),
via format(., scientific=FALSE), see the prI() example
below, or also by increasing global option scipen, e.g.,
options(scipen = 12).
Attributes are printed respecting their class(es), using the values of
digits to print.default, but using the default values
(for the methods called) of the other arguments.
Option width controls the printing of vectors, matrices and
arrays, and option deparse.cutoff controls the printing of
language objects such as calls and formulae.
When the methods package is attached, print will call
show for R objects with formal classes (‘S4’)
if called with no optional arguments.
Large number of digits
Note that for large values of digits, currently for
digits >= 16, the calculation of the number of significant
digits will depend on the platform's internal (C library)
implementation of ‘sprintf()’ functionality.
Single-byte locales
If a non-printable character is encountered during output, it is represented as one of the ANSI escape sequences (‘\a’, ‘\b’, ‘\f’, ‘\n’, ‘\r’, ‘\t’, ‘\v’, ‘\\’ and ‘\0’: see Quotes), or failing that as a 3-digit octal code: for example the UK currency pound sign in the C locale (if implemented correctly) is printed as ‘\243’. Which characters are non-printable depends on the locale. (Because some versions of Windows get this wrong, all bytes with the upper bit set are regarded as printable on Windows in a single-byte locale.)
Unicode and other multi-byte locales
In all locales, the characters in the ASCII range (‘0x00’ to ‘0x7f’) are printed in the same way, as-is if printable, otherwise via ANSI escape sequences or 3-digit octal escapes as described for single-byte locales. Whether a character is printable depends on the current locale and the operating system (C library).
Multi-byte non-printing characters are printed as an escape sequence of the form ‘\uxxxx’ or ‘\Uxxxxxxxx’ (in hexadecimal). This is the internal code for the wide-character representation of the character. If this is not known to be Unicode code points, a warning is issued. The only known exceptions are certain Japanese ISO 2022 locales on commercial Unixes, which use a concatenation of the bytes: it is unlikely that R compiles on such a system.
It is possible to have a character string in a character vector that is not valid in the current locale. If a byte is encountered that is not part of a valid character it is printed in hex in the form ‘\xab’ and this is repeated until the start of a valid character. (This will rapidly recover from minor errors in UTF-8.)
See Also
The generic print, options.
The "noquote" class and print method.
encodeString, which encodes a character vector the way
it would be printed.
Examples
pi
print(pi, digits = 16)
LETTERS[1:16]
print(LETTERS, quote = FALSE)
M <- cbind(I = 1, matrix(1:10000, ncol = 10,
dimnames = list(NULL, LETTERS[1:10])))
utils::head(M) # makes more sense than
print(M, max = 1000) # prints 90 rows and a message about omitting 910
(x <- 2^seq(-8, 30, by=1/4)) # auto-prints; by default all in "exponential" format
prI <- function(x) noquote(format(x, scientific = FALSE))
prI(x) # prints more "nicely" (using a bit more space)