MATLAB: Find numbers that are not in multiple columns

commondeletefindintersectMATLABtable

I have three tables:
A1 =
  5×2 table
    x    Var1   
    __   ____
    1    2524
    2    2342
    3    4353
    4    4353
    5    2348
A2 =
  5×2 table
    x    Var2   
    __   ____
    1    6745
    3    5942
    4    9569
    5    2454
    6    1240
A3 =
  5×2 table
    x    Var3   
    __   _____
    2    4252
    3    9345
    4    9235
    5    1246
    6    3965
For each table I want to find and delete the rows that contains a number in the first row that is not in the first rows of both other tables. So I want to end up with this:
A1 =
  3×2 table
    x    Var1   
    __   ____
    3    4353
    4    4353
    5    2348
  3×2 table
    x    Var2   
    __   ____ 
    3    5942
    4    9569
    5    2454
A3 =
  3×2 table
    x    Var3   
    __   ____
    3    9345
    4    9235
    5    1246
How can I do this? Preferably with no loops.

Best Answer

It looks like you are deleting all rows that do not contain the Var1 value in all 3 tables. Since all the tables will then have the same Var1 values you could combine them into 1 table. Use innerjoin :
% Demo tables
A1 = table((1:5)', rand(5,1))
A1 = 5×2 table
    Var1     Var2  
    ____    _______

     1      0.84504
     2      0.19125
     3      0.23803
     4      0.32501
     5      0.41045

A2 = table([1;3;4;5;6], rand(5,1)) 
A2 = 5×2 table
    Var1     Var2  
    ____    _______

     1       0.7915
     3      0.85265
     4      0.30851
     5       0.1263
     6      0.32535

A3 = table((2:6)', rand(5,1)) 
A3 = 5×2 table
    Var1     Var2  
    ____    _______

     2      0.37713
     3      0.26054
     4      0.91348
     5       0.9767
     6      0.97345

% Join table A1 and A2 to create A12
A12 = innerjoin(A1,A2,'keys', 'Var1');
% Join A12 with A3 to create A123
A123 = innerjoin(A12, A3, 'keys','Var1');
You can rename the variables using A123.Properties.VariableNames = ____
If you'd rather not join the tables 
a12mem = ismember(A1.Var1, A2.Var1);
a13mem = ismember(A1.Var1, A3.Var1);
A1new = A1(a12mem & a13mem,:)
A1new = 3×2 table
    Var1     Var2  
    ____    _______

     3      0.23803
     4      0.32501
     5      0.41045

a21mem = ismember(A2.Var1, A1.Var1);
a23mem = ismember(A2.Var1, A3.Var1);
A2new = A2(a21mem & a23mem,:)
A2new = 3×2 table
    Var1     Var2  
    ____    _______

     3      0.85265
     4      0.30851
     5       0.1263
and repeate for the 3rd table.
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