CODEWITHSUNDEEP
matlabvariablescharacternaming-conventionsmatlab-table
cagatay24
cagatay24

Reputation: 13

MATLAB Column headers not valid variable name

I am working in MATLAB and trying to add units to the Column headers to a table of values then I will insert into SQLite Database but I have a column names of German characters (e.g 'ß', 'ä'), but this is invalid because of the special characters. According to everything I've found thus far has said that column headers must be valid variable names, e.g. alphanumeric and "_" only.

But I can not change my original database column names so does anyone know of a work-around it?

My code of building a table and sending into database is: 

insertData = cell2table(full_matrix,'VariableNames',colnames);
insert(conn,tableName,colnames,insertData);

And some of my column names:

'maß','kapazität', 'räder'

Thank you very much for helping.

Upvotes: 1

Views: 731

Answers (1)

gnovice
gnovice

Reputation: 125854

Do you have to create the table first? I would try just passing the cell array of data directly to insert like so:

insert(conn, tableName, colnames, full_matrix);

The above assumes that it is the cell2table call that is giving you an error related to the special characters. If it's the insert call, then I guess MATLAB won't let you create databases with column names that don't conform to its variable naming conventions. If that's the case, you'll have to convert the column names to something valid, which you can do with either genvarname (for older MATLAB versions) or matlab.lang.makeValidName (suggested for versions R2014a and newer):

colNames = {'maß','kapazität', 'räder'};
validNames = genvarname(colNames);
% or...
validNames = matlab.lang.makeValidName(colNames, 'ReplacementStyle', 'hex');

validNames =

  1×3 cell array

    'ma0xDF'    'kapazit0xE4t'    'r0xE4der'

Note that the above solutions replace the invalid characters with their hex equivalents. You could also change the 'ReplacementStyle' to replace them with underscores or delete them altogether. I would go with the hex values because it gives you the option of converting the column names back to their original string values if you need those for anything later. Here's how you could do that using regexprep, hex2dec, and char:

originalNames = regexprep(validNames, '0x([\dA-F]{2})', '${char(hex2dec($1))}');

originalNames =

  1×3 cell array

    'maß'    'kapazität'    'räder'

Upvotes: 2

Related Questions