[erlang-questions] What's this mean:[1|1]?It's it a bug?
Wed Jul 3 14:34:47 CEST 2013
On Wed, Jul 3, 2013 at 12:09 PM, Ivan Uemlianin <ivan@REDACTED> wrote:
> [1|1] is an "improper list", in other words, a list that doesn't end with
> an empty list . They're valid, but not terribly safe:
> 1> is_list([1|1]).
> 2> length([1|1]).
> ** exception error: bad argument
> in function length/1
> called as length([1|1])
> I don't know if there's any use for them.
It can be used to save two words of memory as [1|1] is two words but [1,1]
is four words. So if you are developing a highly optimized data structure
(like dict for instance) it is useful. Most people will however not need
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