-- produces the union of two tallies.
.
i1 : x = tally {a,b,b,c,c,c,d,d,d}
o1 = Tally{a => 1}
b => 2
c => 3
d => 3
o1 : Tally
|
i2 : y = tally {a,a,a,b,b,c,d}
o2 = Tally{a => 3}
b => 2
c => 1
d => 1
o2 : Tally
|
i3 : x' = new VirtualTally from x
o3 = VirtualTally{a => 1}
b => 2
c => 3
d => 3
o3 : VirtualTally
|
i4 : y' = new VirtualTally from y
o4 = VirtualTally{a => 3}
b => 2
c => 1
d => 1
o4 : VirtualTally
|
i5 : z' = y' - x'
o5 = VirtualTally{a => 2 }
c => -2
d => -2
o5 : VirtualTally
|
i6 : z' + x'
o6 = VirtualTally{a => 3}
b => 2
c => 1
d => 1
o6 : VirtualTally
|
i7 : z' + y'
o7 = VirtualTally{a => 5 }
b => 2
c => -1
d => -1
o7 : VirtualTally
|