Hello Nick
From what I gather, you are trying to fit data to a curve using the Curve Fitter App and you are pre-processing the data to fit the row data using “rows2vars” function.
Curve Fitter App expects numeric data as the input for the ‘X data’ and the ‘Y data’ selection menus. For tables, it automatically identifies the valid columns. For ex. If the table ‘data’ is of the size 11x22 with all the columns having numeric data but column 11 having character data, the Curve Fitter App will let you select all the columns from the ‘data’ table except column 11.
Given that you can see columns from your variable ‘data’, here are some possible scenarios that might explain the behavior you have encountered:
- One of the columns of ‘data’ has entries of datatype ‘char’: In this case, when the table is converted using the “rows2vars” function, the conversion between ‘char’ and numeric datatypes is unsuccessful and the new table is formed with empty entries except for the row with ‘char’ entries. The following code snippet demonstrates this:
data = array2table(rand(11,22)); % Create an 11x22 table with random data
data.Var11 = repmat('a', 11, 1);
Tdata = rows2vars(data)
- One of the columns of ‘data’ has entries of cell or string entries: In this case, the “rows2vars” converts all the entries into cells or strings. The following code snippet demonstrates this:
data = array2table(rand(11,22)); % Create an 11x22 table with random data
data.Var11 = repmat({'a'}, 11, 1);
Tdata = rows2vars(data);
columnDataTypes = varfun(@class, data, 'OutputFormat', 'cell');
% Display the data types
disp('Data Types of All Columns of data:');
for i = 1:width(data)
fprintf('%s: %s\n', data.Properties.VariableNames{i}, columnDataTypes{i});
end
columnTDataTypes = varfun(@class, Tdata, 'OutputFormat', 'cell');
% Display the data types
disp('Data Types of All Columns of Tdata:');
for i = 1:width(Tdata)
fprintf('%s: %s\n', Tdata.Properties.VariableNames{i}, columnTDataTypes{i});
end
Kindly check the datatypes of the entries in the table ‘data’. Due to mismatch of datatypes, the resultant converted table ‘Tdata’ might not contain any numeric column and thus the Curve Fitter App does not identify its columns.
For further understanding, kindly refer to the following MathWorks Documentation:
- Refer to the ‘Select Data to Fit in Curve Fitter App’ section to understand the expected datatypes: https://www.mathworks.com/help/releases/R2023b/curvefit/data-selection.html
- “fit” function to programmatically fit data to a curve: https://www.mathworks.com/help/releases/R2023b/curvefit/fit.html
I hope you find the above explanation and suggestions useful!
