The nil object is an empty object of class
It can be used as a placeholder where such an object of this class, or one
of its subclasses, is required. It serialises to the empty list.
1 2 3
nilObject returns the nil object.
TRUE if its argument is identical to the nil object, or if it is
equivalent in the sense of serialising to an identical result.
Please cite the following reference when using TractoR in your work:
J.D. Clayden, S. Muñoz Maniega, A.J. Storkey, M.D. King, M.E. Bastin & C.A. Clark (2011). TractoR: Magnetic resonance imaging and tractography with R. Journal of Statistical Software 44(8):1-18. http://www.jstatsoft.org/v44/i08/.