[Rd] as.list method for by Objects

[Dario Strbenac]

Good day,

I'd like to suggest the addition of an as.list method for a by object that actually returns a list of class "list". This would make it safer to do type-checking, because is.list also returns TRUE for a data.frame variable and using class(result) == "list" is an alternative that only returns TRUE for lists. It's also confusing initially that

> class(x)
[1] "by"
> is.list(x)
[1] TRUE

since there's no explicit class definition for "by" and no mention if it has any superclasses.

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Dario Strbenac
University of Sydney
Camperdown NSW 2050
Australia