diff ( set1 set2 -- set )
Factor handbook » The language » Collections » Sets » Operations on sets

Prev:	null? ( set -- ? )
Next:	intersect ( set1 set2 -- set )

Vocabulary
sets

Inputs

set1	a set
set2	a set

Outputs

set

a set

Word description
Outputs a set consisting of elements present in set1 but not set2, comparing elements for equality.

This word has a default definition which works for all sets, but set implementations may override the default for efficiency.

Examples

USING: sets prettyprint ; { 1 2 3 } { 2 3 4 } diff .
{ 1 }

See also
intersect, union

Definition

IN: sets

GENERIC: diff ( set1 set2 -- set )

Methods

USING: bit-sets bit-sets.private math sets ;

M: bit-set diff [ bitnot bitand ] bit-set-op ;


USING: hash-sets hash-sets.private kernel sets sets.private ;

M: hash-set diff
    over hash-set? [
        dupd array/tester [ not ] compose
        not-tombstones filter-members >hash-set
    ] [ (diff) >hash-set ] if ;


USING: kernel sets sets.private ;

M: set diff [ (diff) ] keep set-like ;