# rank {base}

### Description

Returns the sample ranks of the values in a vector. Ties (i.e., equal values) and missing values can be handled in several ways.

### Usage

rank(x, na.last = TRUE, ties.method = c("average", "first", "random", "max", "min"))

### Arguments

- x
- a numeric, complex, character or logical vector.
- na.last
- for controlling the treatment of
`NA`

s. If`TRUE`

, missing values in the data are put last; if`FALSE`

, they are put first; if`NA`

, they are removed; if`"keep"`

they are kept with rank`NA`

. - ties.method
- a character string specifying how ties are treated, see ‘Details’; can be abbreviated.

### Details

If all components are different (and no `NA`

s), the ranks are well defined, with values in `seq_len(x)`

. With some values equal (called ‘ties’), the argument `ties.method`

determines the result at the corresponding indices. The `"first"`

method results in a permutation with increasing values at each index set of ties. The `"random"`

method puts these in random order whereas the default, `"average"`

, replaces them by their mean, and `"max"`

and `"min"`

replaces them by their maximum and minimum respectively, the latter being the typical sports ranking.

`NA`

values are never considered to be equal: for `na.last = TRUE`

and `na.last = FALSE`

they are given distinct ranks in the order in which they occur in `x`

.

**NB**: `rank`

is not itself generic but `xtfrm`

is, and `rank(xtfrm(x), ....)`

will have the desired result if there is a `xtfrm`

method. Otherwise, `rank`

will make use of `==`

, `>`

, `is.na`

and extraction methods for classed objects, possibly rather slowly.

### Values

A numeric vector of the same length as `x`

with names copied from `x`

(unless `na.last = NA`

, when missing values are removed). The vector is of integer type unless `x`

is a long vector or `ties.method = "average"`

when it is of double type (whether or not there are any ties).

### References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) *The New S Language*. Wadsworth & Brooks/Cole.

### Examples

(r1 <- rank(x1 <- c(3, 1, 4, 15, 92))) x2 <- c(3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5) names(x2) <- letters[1:11] (r2 <- rank(x2)) # ties are averaged ## rank() is "idempotent": rank(rank(x)) == rank(x) : stopifnot(rank(r1) == r1, rank(r2) == r2) ## ranks without averaging rank(x2, ties.method= "first") # first occurrence wins rank(x2, ties.method= "random") # ties broken at random rank(x2, ties.method= "random") # and again ## keep ties ties, no average (rma <- rank(x2, ties.method= "max")) # as used classically (rmi <- rank(x2, ties.method= "min")) # as in Sports stopifnot(rma + rmi == round(r2 + r2))

Documentation reproduced from R 3.0.2. License: GPL-2.