Accessing data from same variables within different tables in a structural array

Hi, I am fairly new at this, so please bear with me...

I have created a struct 1x20 containing twenty 87x6 tables, each containing data from different patients in a study (n=1:20).

Each table is made up of the same 6 variables: TimeAge, TimeCooling, TempCore, etc.. (others really don't matter).

p(n).data.TimeCooling

p(n).data.TempCore

TimeAge and TimeCooling are both in hours and each range from approximately 0 to 85.

How can I access the data from the tables for specific time points?

I would like to find the mean of the variable TempCore of all patients at the same timepoint. (i.e. I want to know the mean of all patients at TimeCooling = 1 hour, then at 2 hours, etc.)

There is some missing data in TempCore that may need to be accounted for.

Any help would be greatly appreciated!

Answer 1

[Matt J]

fcn=@(p) interp1(  p.data.TimeCooling   ,   p .data.TempCore, timepoints(:));

TempCore_Lookups= cell2mat(arrayfun(fcn,p,'uni',0)) 

result =  mean(  TempCore_Lookups  ,2,'omitnan')

[Jessica L]

Hi Matt J,

Thanks for your response. Unfortunately, it isnt working and I'm getting this error:

Unrecognized function or variable 'timepoints'.

Error in HIE_Code>@(p)interp1(p.data.TimeCooling,p.data.TempCore,timepoints(:)) (line 129)

fcn = @(p)interp1(p.data.TimeCooling, p.data.TempCore, timepoints(:));

If I make a variable (not sure if this is the right approach):

timepoints = 1:85

then I get this error:

Error using interp1>reshapeAndSortXandV (line 438)

X must be a vector of type double or single.

Error in interp1 (line 128)

[X,V,orig_size_v] = reshapeAndSortXandV(X,V);

Error in HIE_Code>@(p)interp1(p.data.TimeCooling,p.data.TempCore,timepoints(:)) (line 130)

fcn = @(p)interp1(p.data.TimeCooling, p.data.TempCore, timepoints(:));

[Matt J]

We need p to be able to reproduce your test. I suggest attaching it in a .mat file.

[Jessica L]

Hi Matt J,

I have attached a simplified/abbridged version of p.

Hopefully this helps to figure out the issue.

[Matt J]

load p

timepoints = 1:85;

TempCore_Lookups= cell2mat(arrayfun(  @(p) process(p, timepoints) ,p,'uni',0)) ;

result =  mean(  TempCore_Lookups  ,2,'omitnan');

plot(timepoints,result)

function out=process(p, timepoints)
%ExtractTime/Temp data from a single structure element, p,  and interpolate
%the data at given timepoints.

 x=p.data.TimeCooling; 
 y=p.data.TempCore;
 
 fin=isfinite(x)&isfinite(y);
 x=x(fin); y=y(fin);  %Remove NaNs (and other nonfinite data)
 
 [x,i]=unique(x);   %Remove duplicate x-values and sort
 y=y(i);            %Obtain corresponding y-values   
 
 out=interp1(x,y,timepoints(:));   %Interpolate (x,y) at the specitified time points
 
end

[Jessica L]

Thank you so much!!

Would you be able to explain a bit of what you did there so I could apply this myself in future?

[Matt J]

Thank you so much!!

You are quite welcome, but please Accept-click the answer to indicate that it did what you want.

Would you be able to explain a bit of what you did there so I could apply this myself in future?

I've added some comments to the code to help understand what it is doing.