MATLAB: Error combining splitapply and regress

Question

Hello,

I have a table named 'T' containing a set of stock returns for different stocks as well as the market return for all days the stock returns are presented. I have divided my table into groups based on the stock and now I am trying to create a regression that uses the stock return as the dependant variable and a constant and the market return as the independant/explainatory variables, however I get the error message 'Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.'

I used the code as follow:

T.Groups = findgroups(T.Numero)
T.Ones = ones(length(T.MarketReturn),1);
X = splitapply(@regress(T.StockReturn,[T.Ones T.MarketReturn]),T,T.Groups);

Answer 1

First argument is just a function handle or an anonymous function -- you mixed metaphors by trying to call a function and call that a handle...

X = splitapply(@(x1,x2,y) regress(y,[x1 x2]),T.Ones,T.MarketReturn,T.StockReturn,T.Groups);