uniqueL function

A Reversable Version of unique()

A version of unique keeping enough information to reverse (or invert) to the original data.

uniqueL(x, isuniq = !duplicated(x), need.sort = is.unsorted(x))

Arguments

• x: numeric vector, of length n, say.
• isuniq: logical vector of the same length as x. For the reversion to work this should select at least all unique values of x.
• need.sort: logical indicating if x is not yet sorted. Note that this argument exists only for speedup possibility when it is known, and that it must be set correctly.

Returns

list of two components, - ix: integer vector of indices

• xU: vector of values from x

such that both x[isuniq] === xU and xU[ix] === x.

Author(s)

Martin Maechler

See Also

Duplicated from the sfsmisc package in addition to the standard unique and duplicated.

Examples

x0 <- c(1:3,2:7,8:4)
 str(r0 <- uniqueL(x0))
 with(r0, xU[ix]) ## == x0 !