How to read specific fields from multiple structure arrays in MATLAB?

Hello,

I have a very large dataset arranged into multiple structure arrays in MATLAB. The structures look something like this:

 Flight1=   
     .testpoint = 1
     .Mach = 0.8
     .Speed = 300
     .Cieling = 35000
     .Data = [A] % A is an MxN matrix

Similarly there are multiple test points for multiple flights. Is there a way to retrieve the Data of only specified test points? For example I want to plot and compare the Data of ALL the test points whose .Mach = 0.8 or where .testpoint = 2?

I hope I have made it clear enough.

Answer 1

[Azzi Abdelmalek]

idx=cellfun(@(x,y) x==2 |y==0.8,{Flight1.testpoint},{Flight1.match})
%idx is the index that fit your conditions

[Azzi Abdelmalek]

You can find the new struct vector

out=Flight1(idx)

[Jay]

Thanks, but this applies to Flight1 data only. I have a directory which includes structure arrays for Flight1, Flight2,...,Flight5 and each of these contains at least 10 substructures (testpoints). I would like to scan the directory and plot the Data for the 2nd test point of each Flight.

[Azzi Abdelmalek]

Your directory can't contain struct variables, but files! How are those variables stored? Unless they are stored in mat files with same names as variables

[Jay]

yes they are stored in mat files (eg. Flight1.mat)

[Azzi Abdelmalek]

for k=1:10
    s=sprintf('Flight%d',k)
    Flight1=load(s)
    idx=cellfun(@(x,y) x==2 |y==0.8,{Flight1.testpoint},{Flight1.match})
    out=Flight1(idx)
    v{k}={out.testpoint}
end

[Jay]

Thanx. This seems to work.

Answer 2

[Thorsten]

A = Flight([Flight.Mach] == 0.8);
B = Flight([Flight.testpoint] == 2);