How to treat an object of a class same as another for a generic

Question

I have classified an object to NewClass, how can I use a function, say plot, on the object as if It's of a known class, say hist?

Konrad Rudolph · Accepted Answer · 2016-09-13T13:33:56.217

1

Simple: just provide the required method:

plot.NewClass = function(x, y, ...) { … }

In the easiest case you can just dispatch to another plot method in the implementation.

If your NewClass object is actually a histogram object in disguise, you can use the following trick:

plot.NewClass = function (x) {
    # “unmask” histogram object
    class(x) = 'histogram'
    plot(x)
}

edited Sep 13 '16 at 13:33

answered Sep 13 '16 at 13:03

Konrad Rudolph

I'm new to r programming so I don't really know the syntax here. How exactly do I dispatch to another plot method(is This case I want to plot as if It's a histogram object) – ChuckP Sep 13 '16 at 13:26
@ChuckP By calling it. Or, in the absolutely simplest case, by just making your function equal to that for a histogram (this requires that these objects are really similar though): `plot.NewClass = graphics:::plot.histogram` — note the three colons: `plot.histogram` isn’t exported from `graphics` so you need to convince R to access a hidden object in the namespace. This is done via `:::`. – Konrad Rudolph Sep 13 '16 at 13:30

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