[R] Finding out the format of an object

Duncan Murdoch murdoch at stats.uwo.ca
Thu Apr 6 20:49:02 CEST 2006

On 4/6/2006 2:24 PM, Thomas L Jones wrote:
> Suppose I have an arbitrary R object. Is there a way to find out its 
> format? There are 118 points, each described by two numbers. Let the 
> name of the object be "obj" without the quotes. I can do a print 
> (obj), but all I get is a bunch of numbers. I can do a ls.str (obj), 
> but all I get is a bunch of numbers. Is it a data frame? A vector with 
> 118 elements, each having two sub-elements? Or ---?
> The object in question is of the class gam (Generalized Additive 
> Model). I know how to pull out some data with the "predict" function, 
> but, when I try to print the value of the predict function, all I get 
> is a bunch of numbers.

str(obj) usually gives you the sort of thing you're looking for.

> Also, how could I have looked this up without having to post a 
> question here?

This is a tricky question.  Usually RSiteSearch() will turn up useful 
information, but I suspect you'll get a lot of false hits if you look 
for "format" or "structure".

Duncan Murdoch

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