How to plot Data from a table filled with strings?

Hello Guys,

I have a problem with plotting Data from a table I get via readtable from a xls-File. The first line of the table is the Measurement-Unit and the following ones are the Measurement-Values. Looking like this:

Now, I am trying to plot the LogTime at the X-Axis and the TalpipeCO2 as Y-Axis. I tried it by getting rid of the first row and converting the table/cell to a matrice using cell2mat. So I can get plottable values using str2num after it. That works for all the Measurement-Signals, but not for the LogTime, saying:

p = app.requestedPlotData.LogTime.(1)(2:end,:)

p =

  2×1 cell array

    {'0'  }
    {'0.1'}

K>> cell2mat(p)
Error using cat
Dimensions of arrays being concatenated are not consistent.

Error in cell2mat (line 83)
            m{n} = cat(1,c{:,n});

Is there a way to plot the data from my tables as they are? Is the conversion from strings to doubles necessary or is there a better way I can't see?

If necessary: The Cell-type in the Excel-File is "Standard"

Code I use for the Data import:

            obj.Conti = readtable(fullfile(path, file),'Sheet','Continuous');

And then I extract one specific column (like TailpipeCO2) outside the function depending on User-Input.

I really appreciate your help. I hope I provides enough information for you to understand my problem

[Stephen23]

Just use str2double on the cell array (this is recommended rather than str2num):

https://www.mathworks.com/help/matlab/ref/str2double.html

[Dominik Kümpflein]

I will! Thank you, Stephen!

Answer 1

[Neuropragmatist]

I think your problem is just that the cell array contains strings of different lengths, you can try converting them to numbers inside the cell array first; for example:

p = app.requestedPlotData.LogTime.(1)(2:end,:)

c = cell2mat( cellfun(@str2num, p, 'un', 0) )

Thanks,

NP.

[Dominik Kümpflein]

That's exactly what I was looking for!

Thank you so much!