is.object                package:base                R Documentation

Is an Object "internally classed"?

Description:

     A function rather for internal use.  It returns 'TRUE' if the
     object 'x' has the R internal 'OBJECT' bit set, and 'FALSE'
     otherwise.  The 'OBJECT' bit is set when a '"class"' attribute is
     added and removed when that attribute is removed, so this is a
     very efficient way to check if an object has a class attribute. 
     (S4 objects always should.)

Usage:

     is.object(x)

Arguments:

       x: object to be tested.

See Also:

     'class', and 'methods'.

     'isS4'.

Examples:

     is.object(1) # FALSE
     is.object(as.factor(1:3)) # TRUE

