finding specific values' rows numbers in an array

a=[11;4;3;99;5;6;7];
b=[4;7];

I need to find which rows in a matrix include 4,7. The answer must be 2th and 7th rows w.r.t. the solution.

Answer 1

[Guillaume]

Use the second return value of ismember:

[~, row] = ismember(b, a)

row will be 0 if the value in b is not found in a.

Answer 2

[Thorsten]

find(a==4)
find(a==7)

[sermet]

how can I adopt this solution as creating loop. Because arrays' rows are several hundreds.