Problem 640. Getting logical indexes

This is a basic MATLAB operation. It is for instructional purposes.

---

Logical indexing works like this.

thresh = 4;
vec    = [1 2 3 4 5 6 7 8];
vi     = (vec > thresh)
vi =
       0     0     0     0     1     1     1     1

Once you have this TRUE FALSE vector (I call it vi: Valid Indices)

It can be used to get the values out:

big = vec(vi)
big =
       5     6     7     8

Given a vector, vec, and a value, v, return a binary vector that represents the indices where vector, vec, is equal to scalar, v.

Note, this works just as well with scalars and matrices.

----

To get the indices where this comparison is true, see this Cody problem.

Solution Stats

51.79% Correct | 48.21% Incorrect
Last Solution submitted on Mar 06, 2024

Problem Comments

Solution Comments

Show comments

Problem Recent Solvers1090

Suggested Problems

More from this Author51

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!