# tally -- tally the elements of a list, sequence, array, or string

## Synopsis

• Usage:
y = tally x
• Inputs:
• x, or ,
• Outputs:
• y, ,

## Description

It produces a hash table (multiset) y which tallies the frequencies of the occurrences of items in the list or string 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 or string.

 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 i5 : tally "Hello, world!" o5 = Tally{ => 1} ! => 1 , => 1 d => 1 e => 1 H => 1 l => 3 o => 2 r => 1 w => 1 o5 : Tally