Characters are what other languages call 'string vectors.'
Input and output
To check whether a value is a character use the
is.character() function. To coerce a variable to a character use the
x <- "The quick brown fox jumps over the lazy dog" class(x)  "character" is.character(x)  TRUE
Note that numerics can be coerced to characters, but attempting to coerce a character to numeric may result in
as.numeric("2")  2 as.numeric("fox")  NA Warning message: NAs introduced by coercion