Unable to call table2array in another function

Hi,

I have a table with only 1 column containing numeric data.

filename = 'dataset_Facebook_modified.csv'; 

data = readtable(filename); 

labels = data(:,end);

Then I want to create a function called 'l_std' where I'm trying to use table2array to carry out some calculations.

function [labels_std, labels_avg] = l_std(labels) 

labels_std = 0; 
labels_avg = 0;
label = table2array(labels);
labels_std = std(label)
labels_avg = mean(label)

end 

However, I got the error message as below (red text):

Brace indexing is not supported for variables of this type.

Error in table2array (line 27)
a = t{:,:};

Error in l_std (line 5)
label = table2array(labels);

When I run it in the main tab, it works fine. I just cannot run it in another function (in another tab).

Can anyone advise where is the error and how to solve it?

Answer 1

[M.Many]

labels = data{:,end};

Use this to directly get labels as an array instead of a table. There is no need to use table2array.

[Walter Roberson]

Note that if you do this, then the function should not do the table2array() step.

[Hanisah Rashid]

Thank you for the answer. But just in case I need to use the variable in the main tab as a table, what causes the error of calling table2array in another function?

[M.Many]

The function l_std just works fine on my side. Maybe the error comes from the table data. Could you paste data(:,end) ?

[Walter Roberson]

what causes the error of calling table2array in another function?

The other function is not passing in a table.

Go to the command line and command

dbstop if error

and then run your function in the other tab (whatever that means to you.) When the problem occurs, give the command

dbup

and then look at class(labels)

[Hanisah Rashid]

Attached is the result of labels as a table.

[Walter Roberson]

And when you did the dbstop and so on, what showed up as class(labels) inside the function ??

[M.Many]

Again the function just works fine with labels on my side. You can add a breakpoint just before the table2array command

function [labels_std, labels_avg] = l_std(labels) 
labels_std = 0; 
labels_avg = 0; %<-- ADD BREAKPOINT HERE (The execution will stop before this command)
label = table2array(labels);
labels_std = std(label)
labels_avg = mean(label)
end

Run the code and then type in the Command window

whos labels

to check if labels is a table

[Hanisah Rashid]

hi both, I did the dbstop if error and dbup to find the class for labels, and apparently I got it as double. However, when I remove the table2array line and change the next to functions to std(labels) and mean(labels), I got the error to run the std function instead due to invalid data type..

[Hanisah Rashid]

I understand that I can set the initial variables directy to arrays and change back to table when I needed it, but I'm just stumped figuring out where I got it wrong.

[Walter Roberson]

We do not know, as we have not seen the code for that other "tab".

I am not even clear what a "tab" is for this purpose?