Makes the elements of a character vector unique by appending sequence numbers to duplicates.
a character vector
a character string used to separate a duplicate name from its sequence number.
The algorithm used by
make.unique has the property that
make.unique(c(A, B)) == make.unique(c(make.unique(A), B)).
In other words, you can append one string at a time to a vector,
making it unique each time, and get the same result as applying
make.unique to all of the strings at once.
If character vector
A is already unique, then
make.unique(c(A, B)) preserves
A character vector of same length as
names with duplicates
changed, in the current locale's encoding.
Thomas P. Minka
1 2 3 4 5 6 7 8