# Fast rank

`frank.Rd`

Similar to `base::rank`

but *much faster*. And it accepts vectors, lists, `data.frame`

s or `data.table`

s as input. In addition to the `ties.method`

possibilities provided by `base::rank`

, it also provides `ties.method="dense"`

.

Like `forder`

, sorting is done in "C-locale"; in particular, this may affect how capital/lowercase letters are ranked. See Details on `forder`

for more.

`bit64::integer64`

type is also supported.

## Arguments

- x
A vector, or list with all its elements identical in length or

`data.frame`

or`data.table`

.- ...
Only for

`list`

s,`data.frame`

s and`data.table`

s. The columns to calculate ranks based on. Do not quote column names. If`...`

is missing, all columns are considered by default. To sort by a column in descending order prefix`"-"`

, e.g.,`frank(x, a, -b, c)`

.`-b`

works when`b`

is of type`character`

as well.- cols
A

`character`

vector of column names (or numbers) of`x`

, for which to obtain ranks.- order
An

`integer`

vector with only possible values of 1 and -1, corresponding to ascending and descending order. The length of`order`

must be either 1 or equal to that of`cols`

. If`length(order) == 1`

, it is recycled to`length(cols)`

.- na.last
Control 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`

.

## Details

To be consistent with other `data.table`

operations, `NA`

s are considered identical to other `NA`

s (and `NaN`

s to other `NaN`

s), unlike `base::rank`

. Therefore, for `na.last=TRUE`

and `na.last=FALSE`

, `NA`

s (and `NaN`

s) are given identical ranks, unlike `rank`

.

`frank`

is not limited to vectors. It accepts `data.table`

s (and `list`

s and `data.frame`

s) as well. It accepts unquoted column names (with names preceded with a `-`

sign for descending order, even on character vectors), for e.g., `frank(DT, a, -b, c, ties.method="first")`

where `a,b,c`

are columns in `DT`

. The equivalent in `frankv`

is the `order`

argument.

In addition to the `ties.method`

values possible using base's `rank`

, it also provides another additional argument `"dense"`

which returns the ranks without any gaps in the ranking. See examples.

## Value

A numeric vector of length equal to `NROW(x)`

(unless `na.last = NA`

, when missing values are removed). The vector is of integer type unless `ties.method = "average"`

when it is of double type (irrespective of ties).

## Examples

```
# on vectors
x = c(4, 1, 4, NA, 1, NA, 4)
# NAs are considered identical (unlike base R)
# default is average
frankv(x) # na.last=TRUE
#> [1] 4.0 1.5 4.0 6.5 1.5 6.5 4.0
frankv(x, na.last=FALSE)
#> [1] 6.0 3.5 6.0 1.5 3.5 1.5 6.0
# ties.method = min
frankv(x, ties.method="min")
#> [1] 3 1 3 6 1 6 3
# ties.method = dense
frankv(x, ties.method="dense")
#> [1] 2 1 2 3 1 3 2
# on data.table
DT = data.table(x, y=c(1, 1, 1, 0, NA, 0, 2))
frankv(DT, cols="x") # same as frankv(x) from before
#> [1] 4.0 1.5 4.0 6.5 1.5 6.5 4.0
frankv(DT, cols="x", na.last="keep")
#> [1] 4.0 1.5 4.0 NA 1.5 NA 4.0
frankv(DT, cols="x", ties.method="dense", na.last=NA)
#> [1] 2 1 2 1 2
frank(DT, x, ties.method="dense", na.last=NA) # equivalent of above using frank
#> [1] 2 1 2 1 2
# on both columns
frankv(DT, ties.method="first", na.last="keep")
#> [1] 2 1 3 NA NA NA 4
frank(DT, ties.method="first", na.last="keep") # equivalent of above using frank
#> [1] 2 1 3 NA NA NA 4
# order argument
frank(DT, x, -y, ties.method="first")
#> [1] 4 1 5 6 2 7 3
# equivalent of above using frankv
frankv(DT, order=c(1L, -1L), ties.method="first")
#> [1] 4 1 5 6 2 7 3
```