Select first

Description

Selecting the first occurrence of an element from a list

Source: The Art of Prolog

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Program source code: select_first.pl

Listing

/*
   select_first(X,Xs,Ys) :- 
	Ys is the list obtained by removing the 
	first occurrence of X from the list Xs.
*/
     select_first(X,[X|Xs],Xs).
     select_first(X,[Y|Ys],[Y|Zs]) :- X \== Y, select_first(X,Ys,Zs).
 
%  Program 7.4    Selecting the first occurrence of an element from a list

Comments

pl/prolog/pllib/select_first.txt · ostatnio zmienione: 2017/07/17 08:08 (edycja zewnętrzna)
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