finding in which row two array has equal values

I have two array with different length A=(500.000,1) and B=(621,1) where all the 621 values of B are included in some of the A rows.

I want to find in which row of A, B will have the same value of A and create a new array C with the result(index)

any idea?

[madhan ravi]

Illustrate with a short example. See if ismember() does what you want.

[Bob Thompson]

ismember, find, or intersect might all be useful for you.

Answer 1

[Adam Danz]

% Create fake data for the example
B = 1:621; 
A = randi(621, 500000, 1); 

% Loop through each element of B, return the row number of matching values in A
resultIdx = cell(size(B)); 
for i = 1:length(B)
   resultIdx{i} =  find(ismember(A,B(i))); 
end

resultIdx{n} lists the rows of A that match the value of B(n).

[Oxeley]

fantastic....ismember() it's could be the instruction that i've searched for a day .

thanks