[R] Finding out the format of an object

[Thomas L Jones]

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.

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

Tom
Thomas L. Jones, Ph.D., Computer Science