| make.names {base} | R Documentation |
Make Syntactically Valid Names
Description
Make syntactically valid names out of character vectors.
Usage
make.names(names, unique = FALSE)
Arguments
names |
character vector to be coerced to syntactically valid names. This is coerced to character if necessary. |
unique |
logical; if |
Details
A syntactically valid name consists of letters, numbers and the dot or
underline characters and starts with a letter or the dot not followed
by a number. Names such as ".2way" are not valid, and neither
are the reserved words.
The character "X" is prepended if necessary.
All invalid characters are translated to ".". A missing value
is translated to "NA". Names which match R keywords have a dot
appended to them. Duplicated values are altered by
make.unique.
Value
A character vector of same length as names with each changed to
a syntactically valid name.
Note
Prior to version 1.9.0, underscores were not valid in variable names,
and code that relies on them being converted to dots will no longer
work. The simplest workaround is to use gsub("_", ".", names).
See Also
make.unique,
names,
character,
data.frame.
Examples
make.names(c("a and b", "a-and-b"), unique=TRUE)
# "a.and.b" "a.and.b.1"
data(state)
state.name[make.names(state.name) != state.name] # those 10 with a space