format(x, ...)
"format"(x, trim = FALSE, digits = NULL, nsmall = 0L, justify = c("left", "right", "centre", "none"), width = NULL, na.encode = TRUE, scientific = NA, big.mark = "", big.interval = 3L, small.mark = "", small.interval = 5L, decimal.mark = getOption("OutDec"), zero.print = NULL, drop0trailing = FALSE, ...)
"format"(x, ..., justify = "none")
"format"(x, ...)
"format"(x, width = 12, ...)
FALSE
, logical, numeric and complex
values are right-justified to a common width: if TRUE
the
leading blanks for justification are suppressed.x
. The default, NULL
, uses
getOption("digits")
. This is a suggestion: enough decimal
places will be used so that the smallest (in magnitude) number has
this many significant digits, and also to satisfy nsmall
.
(For the interpretation for complex numbers see signif
.)0 <= nsmall="" <="20
.=>default
method: the minimum field width or
NULL
or 0
for no restriction. AsIs
method: the maximum field width for non-character
objects. NULL
corresponds to the default 12
.
NA
strings be encoded? Note
this only applies to elements of character vectors, not to numerical,
complex nor logical NA
s, which are always encoded as "NA"
.options("scipen")
).
Missing values correspond to the current default penalty.prettyNum
: that help page explains the details.format
is a generic function. Apart from the methods described
here there are methods for dates (see format.Date
),
date-times (see format.POSIXct
)) and for other classes such
as format.octmode
and format.dist
. format.data.frame
formats the data frame column by column,
applying the appropriate method of format
for each column.
Methods for columns are often similar to as.character
but offer
more control. Matrix and data-frame columns will be converted to
separate columns in the result, and character columns (normally all)
will be given class "AsIs"
.
format.factor
converts the factor to a character vector and
then calls the default method (and so justify
applies).
format.AsIs
deals with columns of complicated objects that
have been extracted from a data frame. Character objects are passed
to the default method (and so width
does not apply).
Otherwise it calls toString
to convert the object
to character (if a vector or list, element by element) and then
right-justifies the result.
Justification for character vectors (and objects converted to
character vectors by their methods) is done on display width (see
nchar
), taking double-width characters and the rendering
of special characters (as escape sequences, including escaping
backslash but not double quote: see print.default
) into
account. Thus the width is as displayed by print(quote =
FALSE)
and not as displayed by cat
. Character strings
are padded with blanks to the display width of the widest. (If
na.encode = FALSE
missing character strings are not included in
the width computations and are not encoded.)
Numeric vectors are encoded with the minimum number of decimal places
needed to display all the elements to at least the digits
significant digits. However, if all the elements then have trailing
zeroes, the number of decimal places is reduced until
nsmall
is reached or at least one
element has a non-zero final digit; see also the argument
documentation for big.*
, small.*
etc, above. See the
note in print.default
about digits >= 16
.
Raw vectors are converted to their 2-digit hexadecimal representation
by as.character
.
The internal code respects the option
getOption("OutDec")
for the decimal mark, so if
this is set to something other than "."
then it takes precedence
over argument decimal.mark
.
format.info
indicates how an atomic vector would be
formatted. formatC
, paste
, as.character
,
sprintf
, print
, prettyNum
,
toString
, encodeString
.
format(1:10)
format(1:10, trim = TRUE)
zz <- data.frame("(row names)"= c("aaaaa", "b"), check.names = FALSE)
format(zz)
format(zz, justify = "left")
## use of nsmall
format(13.7)
format(13.7, nsmall = 3)
format(c(6.0, 13.1), digits = 2)
format(c(6.0, 13.1), digits = 2, nsmall = 1)
## use of scientific
format(2^31-1)
format(2^31-1, scientific = TRUE)
## a list
z <- list(a = letters[1:3], b = (-pi+0i)^((-2:2)/2), c = c(1,10,100,1000),
d = c("a", "longer", "character", "string"),
q = quote( a + b ), e = expression(1+x))
## can you find the "2" small differences?
(f1 <- format(z, digits = 2))
(f2 <- format(z, digits = 2, justify = "left", trim = FALSE))
f1 == f2 ## 2 FALSE, 4 TRUE
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