how to create a for loop 380:780?

Hi,

how can I create a for loop between in this statement

CM4_380 = spec_data(spec_data.wavelength>380 & spec_data.wavelength<381,:);

so it for loops between 380:780? Basically, to make this:

CM4_381 = spec_data(spec_data.wavelength>381 & spec_data.wavelength<382,:);

CM4_382 = spec_data(spec_data.wavelength>382 & spec_data.wavelength<383,:);

CM4_383 = spec_data(spec_data.wavelength>383 & spec_data.wavelength<384,:);

etc. Plus I need to save each of those tables.

Thank you for your help!

Answer 1

[the cyclist]

I would use a cell array, not variable names that also encode an index:

for ic = 380:780
    CM4{ic} = spec_data(spec_data.wavelength>ic & spec_data.wavelength<(ic+1),:);
end

[vicsm]

not working

[the cyclist]

Well, given the tiny amount of information you gave in your question, I would say that it certainly does work.

spec_data = struct('wavelength',381.5);

for ic = 380:780
    CM4{ic} = spec_data(spec_data.wavelength>ic & spec_data.wavelength<(ic+1),:);
end

That code results in exactly what I would expect.

So, instead of just saying "not working", it would be better if you gave more context, uploaded your full code (or at least a portion that we can run), and the full text of any error message you are getting.

[vicsm]

Sorry. Here is my entire code:

load raw_CM4_19.mat

numfiles = length(txtFiles);
spec_data = [];
 
for k = 1:numfiles 
    spec = table(txtFiles(k).wavelength,txtFiles(k).irradiance,'VariableNames',{'wavelength','irradiance'});
    spec = spec(spec.wavelength>380 & spec.wavelength<781,:);
    spec_data = vertcat(spec_data,spec);
end
 
for ic = 380:780
    CM4{ic} = spec_data(spec_data.wavelength>ic & spec_data.wavelength<(ic+1),:);
end

[the cyclist]

I see that my code does indeed give an error here. But for the MAT file you uploaded, spec_data is empty, because numfiles is 0, because txtFiles is empty.

So, it's not a good test case, it seems.

[vicsm]

Well, that's weird because for me it's working just fine...spec_data is 54672x2, because numfiles is 48, because txtFiles is a 48x1 structure.

[the cyclist]

Are you sure you uploaded the file you intended to? In your code, it is called raw_CM_19.mat, but the file you uploaded is raw_CM4_19.mat.

[vicsm]

Thank you for noticing. Indeed, I uploaded the wrong one. Comment edited!

[the cyclist]

So, is there still a problem? Your code runs to completion for me, and fills in the cells I would expect.

[Walter Roberson]

I would suggest

for ic = 380:780
    CM4{ic-380+1} = spec_data(spec_data.wavelength>ic & spec_data.wavelength<(ic+1),:);
end

unless you have a use for CM4{1} to CM4{379}

[vicsm]

I does work, thank you!