mat2list command

[Thomas Ritschel]

I'm trying to convert a one-dimensional matrix (a vector) to a list.

The cataloque menu provides a function called "mat2list" which concatenates the rows of a matrix to just a single row. However, this is still a matrix object with square brackets, e.g. of type "4", which is not what I want (curly braces, type "6").
In contrast the oposite function "list2mat" works as expected.

Is there some other function for this purpose, or maybe some "type conversion"?

Thanks,
Thomas

[massimo]

Assign it to a "L" variable:

L3:=mat2list([[1,2],[3,4]])

Not very elegant, indeed.

Why not use some recursion in a CAS function?

lc(a):=PIECEWISE((length(a)) = 0,{},(length(a))>0,concat({head(a)},lc(tail(a))))

lc([a b c]) returns {a b c}

I like functional languages! BTW this is a classic example of tail recursion. Many functional languages translate it to a loop. It will be nice to know which is the CAS behavior.

[parisse]

Try convert(vector,23)
23 is the subtype of HP lists (Xcas does not make a difference between vectors and lists), 0 is for normal lists, 1 for sequences, 2 for sets.
And the CAS does not try to convert your code to a loop. It is interpreted like it was entered.

[Thomas Ritschel]

(02-18-2014 08:01 AM)parisse Wrote:  Try convert(vector,23)
23 is the subtype of HP lists (Xcas does not make a difference between vectors and lists), 0 is for normal lists, 1 for sequences, 2 for sets.

That's what I was looking for! Thanks!

It's just a bit confusing that CONVERT in Home view means Unit conversion. So one has to use CAS.convert instead...

[parisse]

I'm modifying mat2list to return a HP list.
The same CAS convert command performs list subtype conversion, unit conversion and also some rewriting commands (and in that case you can use STO> as a shortcut, like 1_m Sto> _cm or x^4-1 Sto> * )