Prolog - Changing list items in Prolog

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Author

Changing list items in Prolog

twoflower

2006-02-25, 4:42 am

Hi,

let's have list of some terms, eg. vertex(Id, Height, Excess). I'd like to able to change of the 'attributes' of some vertex in the list, for example:

PHP:


do_something(Height,VertexList) :- member(vertex(Id, Height, Excess), VertexList), % I suppose this runs in O(N), how to change that?

                                     % and now I'd like to change 'Excess' of this vertex

Primitive way how to do it would be to write a predicate which would take the original array and either just copy the vertexes into new array or copy changed vertex to the new array if it is the vertex I want to change. But this takes O(N) time, which is too much...

Is there any approach?

Thank you very much.

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