when using intersect function i need all rows of B and matching rows of A. how can i do it?

i have two varibales A and B of variable sizes for each iteration. lets take first iteration. in 1st iteraton i want to find all rows & column values of B and rows of A which matches with B. and for rows which are not matching i want as zero as given below. like 8542 is not present in A but present in B so in old id column for 8542 i want as zero.

eg.

A id B id

2451 10 2451 15

2554 5 2554 7

5419 2 5419 5

8542 9

i want output like this

B id old id

2451 15 10

2554 7 5

5419 5 2

8542 9 0

Answer 1

[Stephen23]

T1 = array2table([2451,10;2554,5;5419,2],'VariableNames',{'A','id'})

T1 = 3×2 table
     A      id
    ____    __

    2451    10
    2554     5
    5419     2

T2 = array2table([2451,15;2554,7;5419,5;8542,9],'VariableNames',{'B','id'})

T2 = 4×2 table
     B      id
    ____    __

    2451    15
    2554     7
    5419     5
    8542     9

[X,Y] = ismember(T2.B,T1.A);
Y(X) = T1.id(Y(X));
T2.old_id = Y

T2 = 4×3 table
     B      id    old_id
    ____    __    ______

    2451    15      10  
    2554     7       5  
    5419     5       2  
    8542     9       0  

[Suresh R]

thank you!!