How can I add a column to a table based on each csv files name?

I want to write a bunch of csv files together and I am using the following code:

xx = table();
 CSVfileNames = dir('*.csv');
 for kk = 1:numel(CSVfileNames)
     x0 = readtable(CSVfileNames(kk).name);
     xx = [xx; x0];
     oo=table2array(xx)
    xlswrite('AllCSV',oo)
 end

However, within the file I would like an additional column which has the csv file name.

So for example, the first 10 rows would be named the first csv file, the next 10 rows would be the next csv file name etc.

I tried

xx = addvars(xx,CSVfileNames,'Before','Var1');

- but this didnt work.

I am very new to Matlab so please bear with me! I found this code online and have adapted.

Answer 1

[Walter Roberson]

filename = CSVfileNames(kk).name;
x0 = readtable(filename);
x0 = addvars(x0, repmat({filename}, height(x0), 1), 'Before', 'Var1', 'NewVariableNames', 'filename');

[Jessica Dawson]

Great! Thank you so much for your quick reply!

[Jessica Dawson]

Hi Walter,

Thank you for your help with this. Initially this worked when I trialled for a small number of csv files, however, when I tried to combine over 70 files together, I now recieve an error message.

ERROR MESSAGE:

Error using tabular/addvars (line 106)

Unrecognized variable name 'Var1'.

Error in GroupCSVperCond (line 14)

x0 = addvars(x0, repmat({filename}, height (x0), 1),'Before', 'Var1', 'NewVariableNames', 'filename');

When looking at the x0 table, it seems the first row has become the variable column names (e.g NaN, which has meant there is nolonger a Var1). Is there a way to fix this? So the first row doesnt become the column names?

Thanks again for your help!

P.S I tried:

x0 =readtable(CSVfileNames(kk).name,'ReadVariableNames',false);

[Walter Roberson]

'ReadVariableNames',false should solve the problem. However, before R2020a, you might want to do a detectImportOptions on the first file and pass those options to all of the readtable().