| formatC {base} | R Documentation |
Formatting numbers individually and flexibly, using C style
format specifications. format.char is a helper function for
formatC.
formatC(x, digits = NULL, width = NULL,
format = NULL, flag = "", mode = NULL,
big.mark = "", big.interval = 3,
small.mark = "", small.interval = 5,
decimal.mark = ".")
format.char(x, width = NULL, flag = "-")
x |
an atomic numerical or character object, typically a vector of real numbers. |
digits |
the desired number of digits after the decimal
point (format = "f") or significant digits
(format = "g", = "e" or = "fg").
Default: 2 for integer, 4 for real numbers. If less than 0, the C default of 6 digits is used. |
width |
the total field width; if both digits and
width are unspecified, width defaults to 1,
otherwise to digits + 1. width = 0 will use
width = digits, width < 0 means left
justify the number in this field (equivalent to flag ="-").
If necessary, the result will have more characters than width. |
format |
equal to "d" (for integers), "f",
"e", "E", "g", "G", "fg" (for
reals), or "s" (for strings). Default is "d" for
integers, "g" for reals.
"f" gives numbers in the usual
xxx.xxx format; "e" and "E" give n.ddde+nn or
n.dddE+nn (scientific format); "g" and "G" put
x[i] into scientific format only if it saves space to do so.
"fg" uses fixed format as "f", but digits as
the minimum number of significant digits. That this can lead
to quite long result strings, see examples below. Note that unlike
signif this prints large numbers with
more significant digits than digits. |
flag |
format modifier as in Kernighan and Ritchie (1988, page 243).
"0" pads leading zeros; "-" does left adjustment,
others are "+", " ", and "#". |
mode |
"double" (or "real"), "integer" or
"character".
Default: Determined from the storage mode of x. |
big.mark, big.interval,
small.mark, small.interval,
decimal.mark |
used for prettying longer decimal sequences, passed to
prettyNum: that help page explains the details. |
If you set format it over-rides the setting of mode, so
formatC(123.45, mode="double", format="d") gives 123.
The rendering of scientific format is platform-dependent: some systems
use n.ddde+nnn or n.dddenn rather than n.ddde+nn.
formatC does not necessarily align the numbers on the decimal
point, so formatC(c(6.11, 13.1), digits=2, format="fg") gives
c("6.1", " 13"). If you want common formatting for several
numbers, use format.
A character object of same size and attributes as x.
Unlike format, each number is formatted individually.
Looping over each element of x, sprintf(...) is
called (inside the C function str_signif).
format.char(x) and formatC, for character x, do
simple (left or right) padding with white space.
Originally written by Bill Dunlap, later much improved by Martin Maechler, it was first adapted for R by Friedrich Leisch.
Kernighan, B. W. and Ritchie, D. M. (1988) The C Programming Language. Second edition. Prentice Hall.
format, sprintf for more general C like
formatting.
xx <- pi * 10^(-5:4)
cbind(format(xx, digits=4), formatC(xx))
cbind(formatC(xx, wid = 9, flag = "-"))
cbind(formatC(xx, dig = 5, wid = 8, format = "f", flag = "0"))
cbind(format(xx, digits=4), formatC(xx, dig = 4, format = "fg"))
format.char(c("a", "Abc", "no way"), wid = -7) # <=> flag = "-"
formatC( c("a", "Abc", "no way"), wid = -7) # <=> flag = "-"
formatC(c((-1:1)/0,c(1,100)*pi), wid=8, dig=1)
xx <- c(1e-12,-3.98765e-10,1.45645e-69,1e-70,pi*1e37,3.44e4)
## 1 2 3 4 5 6
formatC(xx)
formatC(xx, format="fg") # special "fixed" format.
formatC(xx, format="f", dig=80)#>> also long strings