Sorting Column Variable to a Row

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Huw Wadkin
Huw Wadkin on 16 Jun 2021
Commented: Stephen on 16 Jun 2021
I have been given my data in 3 Columns of a table as depicted in the below screenshot (I have had to try and replicate a similar scenario using excel as I can't share the actual data):
and I wish to have it in this format for easier analysis/plots such as surface plots, with NaN is cells where there is no value for that date and category:
Any help would be appreciated.
Thanks,
Huw

Accepted Answer

Stephen
Stephen on 16 Jun 2021
Edited: Stephen on 16 Jun 2021
Do NOT use loops for this, the inbuilt tools are much better! First lets create some fake data in a table:
C = randi(6,30,1);
D = datetime(2021,1,randi(3,30,1));
T = unique(table(D,C),'rows');
T.V = randi([10,100],height(T),1)/10
T = 15×3 table
D C V ___________ _ ___ 01-Jan-2021 1 8.5 01-Jan-2021 2 6.6 01-Jan-2021 3 4.2 01-Jan-2021 4 1.6 01-Jan-2021 5 8.5 01-Jan-2021 6 8.9 02-Jan-2021 2 7.7 02-Jan-2021 3 3.7 02-Jan-2021 5 3.7 02-Jan-2021 6 1.6 03-Jan-2021 1 7.8 03-Jan-2021 2 5.8 03-Jan-2021 3 7.3 03-Jan-2021 4 3.7 03-Jan-2021 6 4.8
Rearranging how you requested is very easy with just one unstack command:
U = unstack(T,'V','C', 'VariableNamingRule','preserve')
U = 3×7 table
D 1 2 3 4 5 6 ___________ ___ ___ ___ ___ ___ ___ 01-Jan-2021 8.5 6.6 4.2 1.6 8.5 8.9 02-Jan-2021 NaN 7.7 3.7 NaN 3.7 1.6 03-Jan-2021 7.8 5.8 7.3 3.7 NaN 4.8
  3 Comments
Stephen
Stephen on 16 Jun 2021
@Huw Wadkin: what options you have available depends on what MATLAB version you are using, which so far you have not told us. Use the local help of your installed MATLAB to know what options you can use.
"What do these options do?"

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More Answers (1)

SALAH ALRABEEI
SALAH ALRABEEI on 16 Jun 2021
Edited: SALAH ALRABEEI on 16 Jun 2021
Assume your table ( without labels) is of size nx3; where the 1st col is your dates (in numbers), 2nd is your cat, and the 3rd is the values. See this example
x=[ 1 1 1 2 2 2 2 3 3];
y=[0:8];
z=round(100*rand(1,9));
D = [x;y;z]';
a=unique(D(:,1));
B=nan*ones(length(a),size(D,1));
for i = 1:length(a)
B(i,a(i)==D(:,1))=D(a(i)==D(:,1),3);
end

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