how to assign a value to AR model for predicting next step

Hello everyone

I have a code and i estimate a model with AR (auto regressive) and I want to predict next step but it only returns the equation and do not assign value to variable in the equation(z)

Thank you for helping me

clc
clear all
close all
warning off
zafar_queue =readtable('zafar_queue.xlsx');
Y = zafar_queue.nVehContrib;
data = Y';
x_train =  floor(0.9*numel(data));
dataTrain =data(1:x_train);
n = length(dataTrain);
u = 0.1* randn(n,1) ;
Opt = arxOptions;
Opt.InitialCondition = 'estimate';
arx30 = @(z)ar(dataTrain,[30], Opt);
z = 3
frcast = arx30(z)

Result after running code is this and it didn't assign 3 to z

[Hiro Yoshino]

arx30 = @(z)ar(dataTrain,[30], Opt);

This syntax does not do anything for you.

"z" is an argument of the anonymous function arx30 but the "z" is not used for anything.