Re: [Maxima-discuss] How to find duplicate in a list?

[Mario R. <bio...@te...>]

El 10/07/17 a las 04:17, Dr. M Kanagasabapathy escribió:
> Dear Maxima members,
> Is there any specific  function to find the duplicate entries in the list.
> I know the function Unique(L) returns all members in the list but not 
> duplicate.
> It excludes the duplicate.
>
> L: [a,b,a,c,d,f,c]
> In this list
> Duplicate(L) should returns a, c.
>
>
> Thanks for the help.
> Regards

I think we don't have such a function, but we can build one with some 
help of package descriptive:

load(descriptive)$
nfreq(l, k):= submatrix(subsample (transpose(apply(matrix,discrete_freq 
(l))), lambda([v], v[2] = k)),2);

nfreq returns a column matrix with the elements in list l which are 
repeated k times. Examples:

m: [1, 0, 1, 1, 2, 6, 2, 5, 0, 4];
nfreq(m,2); /* duplicated entries */
nfreq(m,3); /* triplicated entries */

-- 
Mario

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