rank {base} R Documentation

## Sample Ranks

### 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 below; 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`.

### References

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

`order` and `sort`.

### 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))
```

[Package base version 2.5.0 Index]