wf {checkmate} | R Documentation |

## Get the index of the first/last TRUE

### Description

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

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

).

### Usage

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

### Arguments

`x` |
[ |

`use.names` |
[ |

### Value

[`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.

### Examples

```
wf(c(FALSE, TRUE))
wl(c(FALSE, FALSE))
wf(NA)
```

[Package

*checkmate*version 2.3.1 Index]