[erlang-questions] list comprehensions speed
Ivan Uemlianin
ivan@REDACTED
Tue Feb 25 15:28:18 CET 2014
There's also lists:keyfind/3 you could try
http://www.erlang.org/doc/man/lists.html#keyfind-3
I think the lists are written in C, so they should be fast.
Ivan
On 25/02/2014 13:08, Oleg wrote:
> Hello.
>
> I'm erlang newbie. Don't beat me, please :-), if this question is obvious.
>
> I have a list of key-value pairs:
>
> A=[{"name1", 1}, {"name2", 77}, {"name3", 33}, {"name4", 234}].
>
> What is faster:
>
> [ Value || {Name, Value} <- A, string:equal(Name, "name3")].
>
> Or:
>
> get_value(Key, []) ->
> [].
> get_value(Key, [H|T]) ->
> {Name, Value} = H,
> case string:equal(Name, Key) of
> true ->
> [Value];
> false ->
> get_value(Key, T)
> end.
>
> start() ->
> get_value("name3", A).
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--
============================================================
Ivan A. Uemlianin PhD
Llaisdy
Speech Technology Research and Development
ivan@REDACTED
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www.linkedin.com/in/ivanuemlianin
festina lente
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