Convert Python list Type to MATLAB double

Hello All,

I would like to convert the python list type to matlab double.

I have tried the following,

First approach

out = func.getValues() %python function gives a list of [1,2,...n]
out = cell(out(1:end-1));
out = cellfun(@double,out); %outputs type double

Second approach

out = func.getValues() %python function gives a list of [1,2,...n]
out = func.convlisttoarray(out) %python function imports numpy and converts list to array using numpy.array()
out_double = double(out); % outputs type double

Although the length of the list is 1x150, in both the approaches, Matlab is taking a lot of computation time and the system hangs for a while. This is wierd to me, as a couple of days earlier everything worked fine and it could solve the problem in milli seconds.

Could anyone of you please help me with a faster approach to convert the python list to matlab double?

I am using Matlab 2019b.

Thank you in advance.

Cheers,

Sai Krishna

Answer 1

[Sean de Wolski]

q = py.list({1,2,3})

q = 
  Python list with no properties.

    [1.0, 2.0, 3.0]

cq = cell(q)

cq = 1×3 cell array
    {[1]}    {[2]}    {[3]}

[cq{:}]

ans = 1×3

1 2 3

[Pol Adillon]

Where does "py." come from?

I get a Not defined Error

[Sean de Wolski]

Do you have python installed and configured? I.e. what's the output of

pyenv

ans = 
  PythonEnvironment with properties:

          Version: "2.7"
       Executable: "/usr/bin/python"
          Library: "libpython2.7.so.1.0"
             Home: "/usr"
           Status: NotLoaded
    ExecutionMode: InProcess

It should not be empty.

[Kent Schonert]

I'm also using 2019b and cannot figure out how to convert python lists to matlab array.

q = py.list({1,2,3})
cq = cell(q)  %errors out in 2019b . . .

Error using cell
Conversion to cell from py.list is not possible.

Later versions of Matlab support this, but not 2019b and below, which I (and my workgroup) am stuck using.