how to set many arrays value at the same time?

Question

I need to check in an array all cells with a value under 9. I build an array with the indexes of those cells using find.

So I have for example array of values

A = [ 2, 10, 3 ]

and array of index

B = [ 1, 3 ]

then I need to set in a new C array the value of index 1 and 3 to 7. How can I do this without a loop?

There's so many duplicates around that Im too lazy to even search — Adriaan, Sep 13 '15 at 18:16
Seems like a job for logical indexing although your last step is kind of unclear. Do you want to set different values at each index, or the same one? — paisanco, Sep 13 '15 at 18:16
@Adriaan what keyword should I use? I don't mind searching except so far I got nothing. — Cher, Sep 13 '15 at 18:26
If Im still awake and capable in a few hours I'll go look for it. [matlab] [array] tags seem like a good start — Adriaan, Sep 13 '15 at 18:32
At the very least, read this post http://stackoverflow.com/questions/32379805/linear-indexing-logical-indexing-and-all-that — user3667217, Sep 13 '15 at 18:34

score 0 · Answer 1 · answered Sep 13 '15 at 18:19

0

You can do this to replace values at certain indices.

C = ones(7,1);
C( [1 3 4 5 6 7] ) = [1 2 3 4 5 6]

answered Sep 13 '15 at 18:19

karakfa

1

That seems rather inefficient. What if you have a hundred, a thousand, a million indices? – Adriaan Sep 13 '15 at 18:20

1 Answers1