why does Matlab return ' expression to the left of the equals sign is not a valid target'

I am using MATLAB 2017a and Python 3.6 I am trying to call a Python script from within the MATLAB window and assign the returned variables to the MATLAB workspace.

I am told by MATLAB help desk that MATLAB does support this version of Python, contrary to what their website says. I have copied my Python folder to my MATLAB pathway as follows:

insert(py.sys.path,int32(0), '/Users/....../Oandafx');

I now attempt to execute the following command in the MATLAB command window

N = py.oandafx.get_history('EUR_USD', granularity='D', prices='BA', count=5)

I get the following error. Can you tell me where I am going wrong?

                                                    ↑
  Error: The expression to the left of the equals sign is not a valid target for an assignment.

Answer 1

[Robert Snoeberger]

MATLAB doesn't support keyword arguments [1]. To pass keyword argument to Python, use pyargs [2].

Example:

N = py.oandafx.get_history('EUR_USD', pyargs('granularity','D','prices','BA','count',5))

1. https://docs.python.org/2/tutorial/controlflow.html#keyword-arguments
2. https://www.mathworks.com/help/matlab/ref/pyargs.html

Answer 2

[Walter Roberson]

It is not legal to have '=' inside MATLAB expressions. You probably need to do a bunch of quoting.

[Charles]

What do you mean. "A bunch of quoting"?

[James Tursa]

E.g., you can't have this as a literal argument:

count=5

You might have to quote the whole thing like this

'count=5'

Same for the other arguments with equal signs. It will depend on what form py.oandafx.get_history accepts.