How to replace values in a matrix?

Hello,

I am fairly new to MATLAB and I have a question. How do you replace a value in a matrix? So if I have a matrix A, where A=3,2,5,-6. How can I find, and replace all of the negative numbers with 0? So I want to end up with a matrix of 3,2,5,0.

Thank you!

Molly

Answer 1

[Star Strider]

One way is to use ‘logical indexing’:

A = [3,2,5,-6];
A(A<0) = 0

A =
     3     2     5     0

Answer 2

[Molly Baltins]

Thank you! This has helped a lot!

[Star Strider]

My pleasure!

[Molly Baltins]

I have another question that hopefully you will be able to help with. I have a string and I want to give each letter a character, but I want it to start off with one. So example I have 'Molly' then it will be [1 2 3 4 5]. Thank you!

[Star Strider]

My pleasure!

I’m not quite certain what you’re asking, so I’ll take a guess at an answer:

str = 'Molly';
result1 = str(1:5)
result2 = str([3 1 5 2 4])

result1 =
Molly
result2 =
lMyol

I used the colon (:) operator to create the subscript vector in ‘result1’. It is the same as typing [1 2 3 4 5].

[Molly Baltins]

Perfect! That is exactly what u wanted! Thank you!

[Star Strider]

Again, my pleasure!