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Macaulay2Doc :: tally(VisibleList)

tally(VisibleList) -- tally the elements of a list, sequence, or array

Synopsis

Description

It produces an hash table (multiset) y which tallies the frequencies of occurrences of items in the list x, i.e., y_i is the number of times i appears in x, or is 0 if i doesn't appear in the list.
i1 : y = tally {1,2,3,a,b,1,2,a,1,2,{a,b},{a,b},a}

o1 = Tally{{a, b} => 2}
           1 => 3
           2 => 3
           3 => 1
           a => 3
           b => 1

o1 : Tally
i2 : y_2

o2 = 3
i3 : y_5

o3 = 0
i4 : y_{a,b}

o4 = 2