| character {base} | R Documentation |
Create or test for objects of type "character".
character(length = 0) as.character(x, ...) is.character(x)
length |
desired length. |
x |
object to be coerced or tested. |
... |
further arguments passed to or from other methods. |
as.character and is.character are generic: you can
write methods to handle specific classes of objects,
see InternalMethods.
as.character represents real and complex numbers to 15 decimal
places (technically the compiler's setting of the ISO C constant
DBL_DIG, which will be 15 on machines supporting IEC60559
arithmetic according to the C99 standard). This ensures that all the
digits in the result will be reliable (and not the result of
representation error), but does mean that coversion to character and
back to numeric may change the number. If you want to convert numbers
to character with the maximum possible precision, use
format.
character creates a character vector of the specified length.
The elements of the vector are all equal to "".
as.character attempts to coerce its argument to character type;
like as.vector it strips attributes including names.
is.character returns TRUE or FALSE depending on
whether its argument is of character type or not.
as.character truncates components of language objects to 500
characters (was about 70 before 1.3.1).
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
paste, substr and strsplit
for character concatenation and splitting,
chartr for character translation and casefolding (e.g.,
upper to lower case) and sub, grep etc for
string matching and substitutions. Note that
help.search(keyword = "character") gives even more links.
deparse, which is normally preferable to
as.character for language objects.
form <- y ~ a + b + c as.character(form) ## length 3 deparse(form) ## like the input a0 <- 11/999 # has a repeating decimal representation (a1 <- as.character(a0)) format(a0, digits=16) # shows one more digit a2 <- as.numeric(a1) a2 - a0 # normally around -1e-17 as.character(a2) # normally different from a1 print(c(a0, a2), digits = 16)