[R] Portected? Variable assignment? Was RE: The use of F for False and T for True

Martin Morgan mtmorgan at fhcrc.org
Mon Nov 17 16:59:24 CET 2008

"Lucke, Joseph F" <Joseph.F.Lucke at uth.tmc.edu> writes:

> The TRUE/FALSE vs. T/F issue brings up a related one.  Can one assign a
> variable a value during an R session that cannot be re-assigned any new
> value during the session?  That is, the variable is `protected' from
> change during the session.  `Session' here is not  precisely defined, so

Environments and their bindings can be locked.

> env <- new.env(parent=emptyenv())
> env[["x"]] <- 10
> lockBinding(env=env, sym="x")
> env[["x"]] <- 11
Error in env[["x"]] <- 11 : cannot change value of locked binding for 'x'


> that will induce some problems.  A reference to this problem would be
> sufficient.
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Martin Morgan
Computational Biology / Fred Hutchinson Cancer Research Center
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