Include an example in list.clean that evaluates using a character

[Ironholds]

list.clean's documentation currently says it can evaluate over "a character". I'm not clear on what this means - it would be good if the documentation had an example.

[renkun-ken]

The argument fun of list.clean can be a character means that it can be, for example, either "is.null" or is.null, both work.

[Ironholds]

Gotcha. Why not 'a function, in quotes or not?'

[renkun-ken]

It works more like *apply functions which accept both function or character using match.fun.