Constructing a structure in matlab - matlab

Question

Could someone please help me in constructing this structure?
As one can see, I have to import this file from excel and convert it into a structure as shown. I have been able to develop a code which can create structures by manually entering Id numbers. For instance if I enter 150 it gives a structure for 150 as shown.
However I have to automate the process, i.e. I want matlab to identify the unique Ids and create the entire structure with all its data and timing in each of its ID.
Here's my code
function [ DynData ] = myfunction( filename )
[dat1, dat2, dat3] = xlsread(filename);
flds = dat3(1,:);
InputData = cell2struct(dat3(2:end,:),flds,2);
uIDs = unique( cell2mat(dat3(2:end, 2))) ;
for j = 1:length(dat3)
uIDs = dat3(j);
i=1;
for k = 2:length(dat3(:,1))
if dat3{k,2} == {uIDs}
IDnumber = ['ID',num2str(uIDs)];
DynData.(IDnumber).time(1,i) = dat3{k,1};
DynData.(IDnumber).ID(1,i) = dat3{k,2};
DynData.(IDnumber).data(1,i) = dat3(k,3);
i=i+1;
end
end
end
end
Any help will be really appreciated!

Answer 1

I prefer to load my .xlsx into tables for easier access.
Try this function:
UPDATE
if id is a number, you cannot use it directly as a field name in your structure. The first character in a field name must be a letter. You can fix this by using a prefix:
function dynData=tableImport(file)
% Imports data from .xls file with columns 'Time' 'Id' 'Data' into
% structure dynData with fieldnames=unique(id) each of which is in turn a
% struct array with fields Time and Data.
% Get data
tab=readtable(file);
% Group by id
G=findgroups(tab.Id);
% Extract id and structure
[id, st]=splitapply(#groupTable,tab,G);
% Build dynData
fieldNames=strsplit(sprintf('id%i\n',id));
for i=1:length(id)
dynData.(fieldNames{i})=st{i};
end
end
function [ID, struc]=groupTable(time,id,data)
% Function for finding id-name and splitting time and data into a struct.
ID=id(1);
struc={struct('Time',num2cell(time),'Data',data)}; % stored in cell
end
Although if I were you I'd rather store my data in a structure array with fieldnames
id (string)
time (array)
data (array/cellarray)
for easier access in for-loops
UPDATE 2
This is what I tried to suggest as a better structure:
function dynData=tableImport2(file)
% Imports data from .xls file with columns 'Time' 'Id' 'Data' into
% structure dynData with fieldnames=unique(id) each of which is in turn a
% struct array with fields Time and Data.
% Get data
tab=readtable(file);
% Group by id
G=findgroups(tab.Id);
% Extract id and structure
dynData=splitapply(#(time,id,data)struct('Id',id(1),'Time',time,'Data',{data}),tab,G);
end