Create or test for objects of type
character(length = 0) as.character(x, ...) is.character(x)
- A non-negative integer specifying the desired length. Double values will be coerced to integer: supplying an argument of length other than one is an error.
- object to be coerced or tested.
- further arguments passed to or from other methods.
is.character are generic: you can write methods to handle specific classes of objects, see InternalMethods. Further, for
as.character the default method calls
as.vector, so dispatch is first on methods for
as.character and then for methods for
as.character represents real and complex numbers to 15 significant digits (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 conversion to character and back to numeric may change the number. If you want to convert numbers to character with the maximum possible precision, use
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. For lists it deparses the elements individually, except that it extracts the first element of length-one character vectors.
FALSE depending on whether its argument is of character type or not.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
as.character breaks lines in language objects at 500 characters, and inserts newlines. Prior to 2.15.0 lines were truncated (at about 70 characters before 1.3.1).
strsplit for character concatenation and splitting,
chartr for character translation and casefolding (e.g., upper to lower case) and
grep etc for string matching and substitutions. Note that
help.search(keyword = "character") gives even more links.
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)
Documentation reproduced from R 3.0.2. License: GPL-2.