Conditional statements on array.

35 views (last 30 days)
Hello MathWorks community!
Could someone give me a hand?
I'm struggling on a loop involving a conditional statement in order to get a particular array.
This is my Input array (1x24):
Input = [0,0,0,0,0,5,6,7,25,68,0,0,0,0,0,36,221,78,14,16,96,75,0,0]
What I'm trying to check is if there is any value bigger than 100 on a 12 range positions of the array. In case the statement is true, I would like to make the 12 range values equal 1, otherwise equal 0. (Note: the array input dimensions will always be a multiple of 12)
The Output on this particular example should look like this:
Output = [0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1]
The first 12 positions are equal to 0 because there aren't any values bigger than 100. But from 13 to 24 postions are equal to 1, because 221 is bigger than 100.
I hope I've explained my-self well enough.
Thanks for the help!

Accepted Answer

Cris LaPierre
Cris LaPierre on 12 Jan 2021
This looks like a job for cummax, along with a logical array (ch 12 MATLAB Onramp).
Input = [0,0,0,0,0,5,6,7,25,68,0,0,0,0,0,36,221,78,14,16,96,75,0,0];
B = cummax(Input);
Output = B >= 100
Output = 1x24 logical array
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
Santos García Rosado
Santos García Rosado on 12 Jan 2021
Great! I was trying to find a way using the cummax documentation you provided. Your code works great anyway. Thank you so much Cris!

Sign in to comment.

More Answers (2)

David Hill
David Hill on 12 Jan 2021
for k=1:size(i,1)
if nnz(i(k,:))>0
  1 Comment
Santos García Rosado
Santos García Rosado on 12 Jan 2021
Thank you for your help David. This works aswell.

Sign in to comment.

Mathieu NOE
Mathieu NOE on 12 Jan 2021
hello Santos
this is one way to do it
split the input vector in 12 long extracts, then search for any value inside that is above your threshold and do some outputs (0 or 1's vectors)
not the fanciest code but it works
Input = [0,0,0,0,0,5,6,7,25,68,0,0,0,0,0,36,221,78,14,16,96,75,0,0];
ll = length(Input);
threshold = 100;
offset = 12;
loops = fix(ll/offset);
Output = [];
for ci = 1:loops
ind = 1+(ci-1)*offset;
input_extract = Input(ind:ind+offset-1);
if any(input_extract >= threshold)
out = ones(1,offset);
out = zeros(1,offset);
Output = [Output out];
  1 Comment
Santos García Rosado
Santos García Rosado on 12 Jan 2021
You're right. Not the fanciest but still works. Thank you!

Sign in to comment.


Find more on Loops and Conditional Statements in Help Center and File Exchange




Community Treasure Hunt

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

Start Hunting!