Replacing values in a matrix

Hello, I'm having trouble figuring out how to replace values in a matrix that fall between two values.

For example, lets say i have matrix, and i want to replace all values that fall between 20 and 50 with -3 instead, how would I go about doing that?

Answer 1

[Adam Danz]

Use basic Matlab indexing.

M(M>20 & M<50) = -3;

[Naoufel Farid]

Thank you this worked great!