Tables: Inner Join using Key 1 or Key 2

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Dom
Dom on 26 Oct 2023
Commented: Voss on 26 Oct 2023
It appears that one can do an inner join in Matlab using key 1 and key 2 - I cannot sem to find a command for Key 1 or Key 2.
Here is some sample data:
i={'A'; 'B';'C';'D';'C';'D';'D';'B';'A'};
j={'B'; 'C';'D';'A';'B';'B';'C';'D';'C'};
i=categorical(i);
j=categorical(j);
v=[10;20;30;40;50;60;70;80;90];
T=table(i,j,v);
i={'A'; 'B'};
i=categorical(i);
j=i;
Tk=table(i,j);
Now I have two tables T and Tk (Tk contains keys).
I would like to join the two tables using two keys T.i=Tk.i or T.j=Tk.j
I could do these separately, for example:
T1=innerjoin(T,Tk,'Keys','i');
T2=innerjoin(T,Tk,'Keys','j');
But there is no way to vertically stack the two tables T1 and T2
Basically the final result should look like this:
i j v
A B 10
B C 20
B D 80
A C 90
A B 10
D A 40
C B 50
D B 60
Thank you,

Accepted Answer

Voss
Voss on 26 Oct 2023
Edited: Voss on 26 Oct 2023
i={'A';'B';'C';'D';'C';'D';'D';'B';'A'};
j={'B';'C';'D';'A';'B';'B';'C';'D';'C'};
i=categorical(i);
j=categorical(j);
v=[10;20;30;40;50;60;70;80;90];
T=table(i,j,v)
T = 9×3 table
i j v _ _ __ A B 10 B C 20 C D 30 D A 40 C B 50 D B 60 D C 70 B D 80 A C 90
i={'A';'B'};
i=categorical(i);
j=i;
result = [T(ismember(T.i,i),:); T(ismember(T.j,j),:)]
result = 8×3 table
i j v _ _ __ A B 10 B C 20 B D 80 A C 90 A B 10 D A 40 C B 50 D B 60
Or if you don't care about that specific row ordering or repeating the row where both T.i and T.j are in {'A';'B'}:
% result = T(ismember(T.i,i) | ismember(T.j,j),:) % alternative
result = T(any(ismember([T.i,T.j],i),2),:) % works only because i == j
result = 7×3 table
i j v _ _ __ A B 10 B C 20 D A 40 C B 50 D B 60 B D 80 A C 90
  2 Comments
Dom
Dom on 26 Oct 2023
Thank you Voss. Much appreciated. Thanks also for including the 7x3 alternative which excludes the duplicated row: A B 10.

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