how can I define a global variable in app designer?

Question

Matteo Paolucci 2020-8-16

2
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https://ww2.mathworks.cn/matlabcentral/answers/580332-how-can-i-define-a-global-variable-in-app-designer

编辑： Stephen23 2024-9-2

I have to built an app that read data in .csv file and then display and process them.

[file,path] = uigetfile;
tab=readtable(fullfile(path,file));

I used this code for import and save the data but I don't know how can I set them as 'Global variables'.

Can someone help me ?

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Kevin Andres Contreras 2020-9-30

¿Me puedes ayudar?

No me quiere copilar

Matteo Paolucci 2020-10-3

编辑：Matteo Paolucci 2020-10-3

在 MATLAB Online 中打开

when you have a variable in app designer, it is not saved as when you'd work on command window. If you want use a variable like 'global variable' in app designer you can do this using 'Properties'.

to be clear:

in this following code the variable y can not be 'seen' in other parts of your code. So you have to write app.variablename and write variablename under the part 'Properties' (it is generated automatically).

x = 1:0.1:100;
app.y=cos(x)

in this way you can use your variable every time you want.

so you have to:

1) use app.variablename for variable you want use in other parts of your code. you have to use app.variablename evry time you call it

2) write variablename under the part of code called 'Propeties'

if you have any difficulties you can write me an email

paolucci.1806891@studenti.uniroma1.it

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Answer 1

Adam Danz 2020-8-16

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https://ww2.mathworks.cn/matlabcentral/answers/580332-how-can-i-define-a-global-variable-in-app-designer#answer_480729

编辑：Adam Danz 2020-10-4

There are very few reasons, if any, to use global variables in apps and it's usually the sign of trouble.

If the variable is meant to be shared with other functions within the app, declare it as a private variable. If the variable is also needed by external functions or scripts, declare it as a public variable. The link below shows how to do both.

https://www.mathworks.com/help/matlab/creating_guis/share-data-across-callbacks-in-app-designer.html

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Chikezie Onyema 2024-9-2

How about loading a very large mat file each time I run app in app designer? How can you not spend minutes loading a file if you have to run the program each time during coding and testing?