CODEWITHSUNDEEP
prologprolog-setof
niyidrums
niyidrums

Reputation: 13

Prolog setOf with Multiple Predicates

In my prolog database, I have below facts:

played('Sharon rose', piano).
played('Robert Kay', piano).
played('Kelvin Cage', drums).
singer('Robert Kay').
band_leader('Sharon rose').

I want to print out all the names uniquely as a single list.

Below is my query using setof and the output:

setof(X, (played(X,_);singer(X);band_leader(X)), Output).

Output = ['Robert Kay','Sharon rose'] ? ;

Output = ['Kelvin Cage'] ? ;

Output = ['Robert Kay','Sharon rose']

yes

However, the output isn't what I want. I want it to print out the names uniquely as a list.

Upvotes: 1

Views: 78

Answers (1)

Paulo Moura
Paulo Moura

Reputation: 18663

You get multiple answers due to the anonymous variable in the goal argument of setof/3. Try instead:

?- setof(X, Y^(played(X,Y);singer(X);band_leader(X)), Output).

Upvotes: 1

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