Reshape list into columns

Im working with driving data for vehicles. There is 429 vehicles (DeviceStats). For the trips, there is a list of 107910 rows with one value per row (Car). The value is the id number of the vehicles. The format of the list looks like this

173

173

173

178

178

184

and so on. Every vehicle has a different number of vehicles in the Car vector. I want to reshape the list to 429 columns, where each column has the length the same length as the vehicle has in the Car-list. Like this

173 178 184

173 178

173..

My approach so far has not worked:

clc

clear

load EXJOBB

D=[];

Car=tripStats.device;

Devicestats=deviceStats.device;

for j=1:429

for i=1:107910

if Car(i)==Devicestats(j)

D(i,j)=[Car(i)];

else

break

end

end

end

[Joel Schelander]

*There is 429 vehicle id numbers

[Stephen23]

Matrices must be rectangular, i.e. all rows have the same number of columns, all columns have the same number of rows.

Gaps, missing data, holes, rows or columns of different lengths are not supported.

Do you want to:

• pad the columns with some default value, e.g. 0, NaN, etc. (if so, what value?)
• use a container array (e.g. cell array) to hold numeric vectors of different lengths?

[Joel Schelander]

Yes, padding with 0 seems legit.

First vehicle has 224 trips, second has 136. First vehicle has id number 173, second id-number 178

I tried with this for-loop

A=[];

for j=1:429

for i=1:107910

if Car(i)==Devicestats(j)

A(i,j)=[Car(i)}]

elseif Car(i)<Devicestats(j)

break

end

end

end .

So in the end I want a cell array which contains the vectors of different sizes. This code only result in the first vehicle (224*1)

Answer 1

[Gargi Patil]

I understand that you would like to create a matrix with each column containing same elements and each row having unique elements.

You have asked a similar question here which has been answered:

https://in.mathworks.com/matlabcentral/answers/759536-changing-input-data-sample-from-the-same-dataset?s_tid=answers_rc1-1_p1_Topic

To extend the above solution further:

list = [173 173 173 178 178 184]; 

%Get unique elements in list
uniqueEle=unique(list(:,1)); 
num = numel(uniqueEle); 
res = zeros(num,num); 
ii = 1; 
 
for i = 1:numel(uniqueEle) 
    output = list(list(:,1)==uniqueEle(i),:); 
    %Append zeros to make output of length num
    output((end+1):num,1)=0; 
    res(:, ii) = output; 
    ii = ii + 1; 
end 

res will return the desired output matrix.

The rows can be converted to cell arrays using num2cell().