Extract Positions in redundant dimension table — keypos • bit64

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

keypos(x, ...)

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

Arguments

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

Value

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

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)
orderkey (memory saving ordering).

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)
#>  [1]  1  1  1  6  1  1  1  9  1  1  1  9  8  8  1  1  1  1  7  1  6  3 10  1  8
#> [26]  4  5  9  1  2  1  1

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