[R] Is = now the same as <- in assigning values

Wacek Kusnierczyk Waclaw.Marcin.Kusnierczyk at idi.ntnu.no
Tue Dec 16 08:01:30 CET 2008

Petter Hedberg wrote:
> I´m a PhD student at the University of Warsaw, and have started using R.
> In many books they specify to use <- instead of = when assigning
> values, and this is also mentioned in older posts on the R website.
> However, it seams to me that some update has occured, becuase I
> continously get the same result wether I use <- or =.
> I would be extremely helpful for any answer to this.
> = seams more intuitive, so I assumed that an update had been made due
> to popular demand and that was why I get the same output wether I use
> <- or =.


<- and = are not exactly equivalent.  while in many situations you may
use = instead of <-, in some you can't:

x <- 1
x = 1
# same thing

foo = function(a) ...

foo(x <- 2)
# assign to x, and pass it to foo as the argument a

foo(x = 2)
# pass 2 to foo as the argument x

personally, i prefer = to <- wherever possible, but some on this list
have expressed the opinion that such code is rather annoying.  it seems
to be a matter of taste, but you may want to stay in the mainstream and
get used to <-.


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