Inverse Which

The inverse function to which creates a logical vector/matrix from indices.

Unwhich(idx, n, useNames = TRUE)

Arguments

idx

the indices as returned by which.

n

integer, the length of the original vector.

useNames

logical, determining if the names of the indices should be preserved.

Value

a logical vector of the length n, with TRUE on the positions i.

References

https://stackoverflow.com/questions/7659833/inverse-of-which

Author

Nick Sabbe

See also

which

Examples

ll <- c(TRUE, FALSE, TRUE, NA, FALSE, FALSE, TRUE)
names(ll) <- letters[seq(ll)]
i <- which(ll)
# back again (loosing the names of the FALSEs)
Unwhich(i, length(ll))
#>     a  <NA>     c  <NA>  <NA>  <NA>     g 
#>  TRUE FALSE  TRUE FALSE FALSE FALSE  TRUE