A quick C implementation for “which.first” (`head(which(x), 1)`

) and
“which.last” (`tail(which(x), 1)`

).

wf(x, use.names = TRUE) wl(x, use.names = TRUE)

x | [ |
---|---|

use.names | [ |

[`integer(1)`

| `integer(0)`

].
Returns the index of the first/last `TRUE`

value in `x`

or
an empty integer vector if none is found. NAs are ignored.

#> [1] 2#> integer(0)wf(NA)#> integer(0)