Scanning a column in matrix with repeated values

4 views (last 30 days)
There are four coulmns (Subject, Number, ID, ANS) in a table named 'List'. I initialized a structure with each cell having zero matrices for unique value in subject list based on below code. Once this is done I want to scan the column Subject(which has repeated values) and place the ANS value of each row in the Zero matrix of that subject number at 'IDxNumber' (index). This repeates for every subject value found in the Subject column which is 10 next.
List table
Subject Number ID ANS
9 1 10 -1
9 2 10 1
9 3 10 -1
10 1 5 1
10 2 6 -1
c = 1;
for b = 1:max(List.Subject)
for a = 1:length(List.Subject)
if List.Subject(a) == b
count_id = sum(List.Subject(:) == b);
Subject_Assist{c} = zeros(101,count_id);
c = c+1;

Sign in to comment.

Accepted Answer

the cyclist
the cyclist on 19 Dec 2018
Edited: the cyclist on 19 Dec 2018
This code does the initialization. I'm still trying to figure out what you mean about filling it in.
[Edited afterward to fill in.]
% The original data
Subject = [9;9;9;10;10];
Number = [1;2;3;1;2];
ID = [10;10;10;5;6];
ANS = [-1;1;-1;1;-1];
% The original table
List = table(Subject,Number,ID,ANS);
% Find the unique subjects, and their corresponding rows
[uniqueSubject,~,indexFromUniqueBackToAll] = unique(List.Subject);
numberUniqueSubjects = numel(uniqueSubject);
% Create a cell array with one element per subject
output = cell(numberUniqueSubjects,1);
% For each subject ...
for ns = 1:numberUniqueSubjects
% Index that subject;s rows
indexThisSubjectsRows = find(indexFromUniqueBackToAll==ns);
numberRowsThisSubject = numel(indexThisSubjectsRows);
% initialize a matrix of zeros of apprpriate size
output{ns} = zeros(101,numberRowsThisSubject);
% Fill in ANS at the indicated rows
for ni = 1:numberRowsThisSubject
output{ns}(List.ID(indexThisSubjectsRows(ni)),List.Number(indexThisSubjectsRows(ni))) = List.ANS(indexThisSubjectsRows(ni));
Sunny on 20 Dec 2018
I figured out the issue its due to NaN. Thanks

Sign in to comment.

More Answers (0)


Find more on Tables in Help Center and File Exchange




Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by