I want to replace strings in a column of a structure (see the picture) with numbers/codes. Can someone help with this??

I have several strings in a column of a structure. They were imported to matlab through eeglab. The strings that I'm interested in are "stm+" and "resp" (you can see the picture attached). I want to replace them with number 1 and 3, respectively.

[Walter Roberson]

Do you want to replace them with "1" and "3" or with numeric 1 and 3? Because if you want to replace them with numeric 1 and 3, you would have to deal with the fact that the rest of the column is going to remain string.

[Marco]

They need to be numerical values. Your answer below worked well though.

Answer 1

[Walter Roberson]

codestrings = {'bgin', 'resp', 'stm+', 'TRSP'};
codevals = [-2, 3, 1, -4];
[found, index] = ismember(YourTable.columnlabel, codestrings);
codes = nan(height(YourTable), 1);
codes(found) = codevals(index(found));

This inserts nan for any unrecognized string, and whatever value is in codevals for recognized strings.

[Marco]

Thank you! I could use only the first 3 lines. FYI, I run this:

index=num2cell(index);

and

[YourTable.columnlabel]=index{:};

So I could replace the whole column in the structure I need.

Thanks!

[Walter Roberson]

You could have just used

YourTable.columnlabel = codes;

codes was already constructed as a column vector the correct size (the nan initialization took care of that), and when you use dot notation to assign to a table variable, the type of the variable will be changed if needed.