Question

I want to write a function which filters a list of numbers by removing everything less than or equal to a specific number. The function will take two parameters: a list of numbers and the number to filter. The function should returns a list which has all the numbers larger than the filter number.

Sometime like this:

filter_num_list(L1,N,L2) :- ...

test_filter_num_list :- filter_num_list([1,2,3,4,5,6,7,8,9],5,[5,6,7,8,9]).

Answer 1

try something like:

filter_num_list([],N,[]) :- true.  
filter_num_list([H|T],N,[H|S]) :- H > N,filter_num_list(T,N,S).  
filter_num_list([H|T],N,S) :- N >= H, filter_num_list(T,N,S).