Optional: Optional types
In tractor.base: Read, Manipulate and Visualise Magnetic Resonance Images
Optional R Documentation
Optional types
Description
This function declares an optional type, a union of the named class (which
must already be defined) and NULL. It is meant for use in packages.
Usage
Optional(className)
Arguments
className
A string naming an existing (S4) class.
Value
The name of the union class (invisibly), which will be the original
class name with "Optional" prepended to it.
Author(s)
Jon Clayden
References
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. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v044.i08")}.
See Also
setClassUnion
tractor.base documentation built on Nov. 5, 2025, 6:18 p.m.
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| Optional | R Documentation |
Optional types
Description
This function declares an optional type, a union of the named class (which
must already be defined) and NULL. It is meant for use in packages.
Usage
Optional(className)
Arguments
className |
A string naming an existing (S4) class. |
Value
The name of the union class (invisibly), which will be the original class name with "Optional" prepended to it.
Author(s)
Jon Clayden
References
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. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v044.i08")}.
See Also
setClassUnion
R Package Documentation
Browse R Packages
We want your feedback!
Note that we can't provide technical support on individual packages. You should contact the package authors for that.
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