How to pass tuple to a Matlab function from Python

Question

I have a Matlab function that I'm calling from a python script:

import matlab.engine

eng = matlab.engine.start_matlab()
t = (1,2,3)
z = eng.tstFnc(t)
print z

The function tstFnc is as follows:

function [ z ] = tstFnc( a, b, c )
z = a + b + c

This does not work, however, as Matlab receives one input instead of three. Could this be made to work?

Note: this is a simplified case of what I want to do. In the actual problem I have a variable number of lists that I pass into a Matlab function, which is interpreted in the Matlab function using varargin.

Try `z = eng.tstFnc(*t)` to apply the arguments instead of passing them as a tuple — Pyrce, Sep 02 '15 at 17:05

Pyrce · Accepted Answer · 2015-09-02T17:50:45.187

3

As notes in the comments, the arguments need to be applied instead of passed as a tuple of length 1.

z = eng.tstFnc(*t)

This causes a call to tstFnc with len(t) arguments instead of a single tuple argument. Similarly you could just pass each argument individually.

z = eng.tstFnc(1, 2, 3)

edited Sep 02 '15 at 17:50

answered Sep 02 '15 at 17:10

Pyrce

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I should add that `t = (2,3)` and `z = eng.tstFnc(1, *t)` works too, in case anyone is curious. – sodiumnitrate Sep 02 '15 at 18:49
@sodiumnitrate - Yes, that's a standard Pythonic way of splitting up the tuple. BTW, I've already +1ed your question and this answer. – rayryeng Sep 02 '15 at 19:47
@rayryeng Yeah, ok, I didn't know :) Thanks! – sodiumnitrate Sep 02 '15 at 20:57

How to pass tuple to a Matlab function from Python

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