R: Extract Positions in redundant dimension table

keypos {bit64} | R Documentation

## Extract Positions in redundant dimension table

### Description

`keypos` returns the positions of the (fact table) elements that participate in their sorted unique subset (dimension table)

### Usage

    keypos(x, ...)
    ## S3 method for class 'integer64'
    keypos(x, method = NULL, ...)

### Arguments

`x` | a vector or a data frame or an array or `NULL`.
`method` | NULL for automatic method selection or a suitable low-level method, see details
`...` | ignored

### Details

NAs are sorted first in the dimension table, see `ramorder.integer64`.
This function automatically chooses from several low-level functions considering the size of `x` and the availability of a cache. Suitable methods are `sortorderkey` (fast ordering) and `orderkey` (memory saving ordering).

### Value

an integer vector of the same length as codex containing positions relativ to codesort(unique(x), na.last=FALSE)

### Author(s)

Jens Oehlschlägel <Jens.Oehlschlaegel@truecluster.com>

### See Also

`unique.integer64` for the unique subset and `match.integer64` for finding positions in a different vector.

### Examples

    x <- as.integer64(sample(c(rep(NA, 9), 1:9), 32, TRUE))
    keypos(x)

    stopifnot(identical(keypos(x),  match.integer64(x, sort(unique(x), na.last=FALSE))))

[Package bit64 version 0.9-7 Index]