How to find the index of a column data whose values are equal to another column data?

For example:

A = [31; 2; 57; 36; 87; 36];
B = [2; 36];

My goal is to find the inex of all the column A that are equal to any elements of B. In this case, the answer would be:

Ind = [0; 1; 0; 1; 0; 1];

For both A and B, I have extramely large number of rows, so it won't be efficient to write a loop. What is the most efficient way to performace this task?

Many thanks.

Answer 1

[the cyclist]

A = [31; 2; 57; 36; 87; 36];
B = [2; 36];

Ind = ismember(A,B)

Ind = 6×1 logical array
   0
   1
   0
   1
   0
   1

[Leon]

Very cool. Glad to know there is a function specifically for that. Many thanks.