R: Backport of .valid.factor for R < 3.4.0

.valid.factor {backports} | R Documentation

## Backport of .valid.factor for R < 3.4.0

### Description

See the original description in `base::.valid.factor`.

### Usage

    .valid.factor(object)

### Examples

    # get function from namespace instead of possibly getting
    # implementation shipped with recent R versions:
    bp_.valid_factor = getFromNamespace(".valid.factor", "backports")
    bp_.valid_factor(factor(letters[1:3]))

[Package backports version 1.1.2 Index]