Wacek Kusnierczyk wrote:
Wacek Kusnierczyk wrote:
it's a pity that <<- is not explained in ?`<<-` clearly enough:
" The operators '<<-' and '->>' cause a search to made through the
environment for an existing definition of the variable being
assigned. If such a variable is found (and its binding is not
locked) then its value is redefined, otherwise assignment takes
place in the global environment. Note that their semantics differ
from that in the S language, but are useful in conjunction with
the scoping rules of R. See 'The R Language Definition' manual
for further details and examples."
the description is further imprecise as to what happens if such a
variable is found but is locked:
foo = function() {
x = 0
lockBinding("x", environment())
(function() x <<- 1)()
unlockBinding("x", environment())
}
foo()
# error
if analysed logically (IF (found AND not locked THEN assign) ELSE assign
globally), the description is wrong.
Yes.
If such a variable is found then its value is redefined (unless its
binding is locked), otherwise assignment take place in the global
environment.
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalga...@biostat.ku.dk) FAX: (+45) 35327907
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