# Reshape list into columns

2 views (last 30 days)
Joel Schelander on 2 Mar 2021
Answered: Gargi Patil on 15 Apr 2021
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
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 on 2 Mar 2021
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)

Gargi Patil on 15 Apr 2021
I understand that you would like to create a matrix with each column containing same elements and each row having unique elements.
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().

R2019a

### Community Treasure Hunt

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

Start Hunting!