How to collect a new variable each time a function runs and save it into an array

Hi, I have a program that is collecting a variable each time it is run through the function (every minute) and it collects a variable called 'VWAP'.

How do I save this data so next time the function runs it will save the new value of the variable in an array so all the values can saved for analysis later?

I was looking at mlock, but I am not sure how to use that to build an array.

Any assistance even directional is appreciated. thanks

Allan

function processContracts(contracts, params)

datavwap = IQML('quotes','Symbol','ACB','Fields',{'Bid','Ask','Last','VWAP','time'});

end

[Rik]

A persistent variable would be a good start. You may also want to consider using a class.

[Allan Munro]

Thanks for the help!!! Very Informative!

Answer 1

[Raynier Suresh]

This can be done by using either “Persistent” or “Global” variable.

Refer the below code:

function myFun(x)
    persistent n;
    n = [n x]
end

myFun(10)
n =
     10
myFun(12)
n = 
     10    12

If in case its necessary to move the variable from the function to base workspace you can use “assignin”

Refer the below links for more information:

https://www.mathworks.com/help/matlab/ref/persistent.html

https://www.mathworks.com/help/matlab/ref/global.html

https://www.mathworks.com/help/matlab/ref/assignin.html

[Rik]

Both global and assignin should be considered hacks and are rarely if ever needed.