Arrays vs tuples / lists

Carsten Schultz <>
Tue May 18 14:21:32 CEST 2004


On Tue, May 18, 2004 at 01:05:35PM +0200, Thomas Johnsson wrote:
> Hi,
> thanks for doing the benchmarking for me.
> One note: the ets lookup is done with
>    [X] = ets:lookup(Tab, Pos),
> which involves a pattern matching on the lhs, that has a cost.
> Could you re-run it on the same box, with
>     X = head(ets:lookup(Tab, Pos)),
> 
> or some such? Head must do a similar check, but presumably it is cheaper.

If the second version is faster, then the Erlang compiler is stupid,
and I do not think that it is.

Or is there any semantic difference between the two that I have
overlooked?

Greetings,

Carsten

-- 
Carsten Schultz (2:38, 33:47), FB Mathematik, FU Berlin
http://carsten.fu-mathe-team.de/
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