Six variations on ranking functions, mimicing the ranking functions
described in SQL2003. They are currently implemented using the built in
rank function, and are provided mainly as a convenience when
converting between R and SQL. All ranking functions map smallest inputs
to smallest outputs. Use desc to reverse the direction..
Usage
row_number(x)
ntile(x, n)
min_rank(x)
dense_rank(x)
percent_rank(x)
cume_dist(x)
Arguments
x
a vector of values to rank. Missing values are left as is.
If you want to treat them as the smallest or largest values, replace
with Inf or -Inf before ranking.