Character Objects

DESCRIPTION:

Creates or tests for objects of mode character. There is a big data analog; see .

USAGE:

character(length=0) 
is.character(x) 
as.character(x) 

OPTIONAL ARGUMENTS:

length
integer giving the length of the returned object.

x
any S-PLUS object.

VALUE:

character returns a character vector of the length specified, containing null strings ( "").

is.character returns TRUE if x has mode "character". Otherwise, it returns FALSE. Its behavior is unaffected by any attributes of x; for example, x could be a character array (in contrast to the behavior of is.vector).

as.character returns x if x is a simple object of mode "character". Otherwise, it returns a character vector of the same length as x and with data resulting from coercing the elements of x to mode "character".

To convert a bdCharacter to a character, you must call bd.coerce.

DETAILS:

Both the is.character and as.character functions are generic; currently there are no methods written for them.

Simple objects have no attributes. Data elements of objects of mode "character" are character strings. In most S-PLUS expressions it is not necessary to explicitly ensure that data are of a particular mode. For example, the function paste does not need character arguments; it will coerce data to character as needed.

Note the difference between coercing to a simple object of mode "character" and setting the mode attribute: mode(myobject) <- "character" This changes the mode of myobject but leaves all other attributes unchanged (so, for example, a matrix stays a matrix). On the other hand, the value of as.character(myobject) has no attributes.

When using ascii codes in a character string, "\n" and "\t" denote ascii newline and tab characters, respectively, "\\" denotes a backslash, and "\"" represents a quote within a string. Some other C escape sequences are allowed but are not supported. Arbitrary ascii codes may be included by "\nnn" where nnn is a 3-digit number in octal notation (e.g. "\012" is the same as "\n"). For a list of ascii characters, see help(ascii).

SEE ALSO:

, , , , , , .

EXAMPLES:

character(length(zz)) # a character object the same length as zz 
as.character(1:10) # character representations of 1,2,...,10