[erlang-questions] Getting the position of a list item
Igor Ribeiro Sucupira
Wed Dec 2 18:53:04 CET 2009
I happened to need that once and ended up implementing my own, so I
think you won't find it in the standard library.
Later, I realized there was a more elegant way of doing what I wanted,
so I should agree with Robert in that you probably don't need that
functionality (but we could be wrong, of course...).
find_first(Element, List) when is_list(List) ->
find_first(Element, List, 0).
find_first(_Element, , Inc) when is_integer(Inc) ->
Inc + 1;
find_first(Element, [Element | _Tail], Inc) when is_integer(Inc) ->
Inc + 1;
find_first(Element, [_ | Tail], Inc) when is_integer(Inc) ->
find_first(Element, Tail, Inc + 1).
On Wed, Dec 2, 2009 at 3:10 PM, Garrett Smith <g@REDACTED> wrote:
> I'm missing something basic here :\
> The lists module has keyfind/3 but no find/2, where you want to return
> the position of a particular list item. This is surprising.
> Is there a commonly used pattern for this?
"The secret of joy in work is contained in one word - excellence. To
know how to do something well is to enjoy it." - Pearl S. Buck.
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