find max value of structure

199 views (last 30 days)
FV on 5 May 2020
Commented: Image Analyst on 27 Sep 2023
I have a small problem today.
I have gotten a struct that's 1x30 and it's just 30 values in the one column. It shoudn't be so hard but I need to find the max values of these. But somehow I cant do this.
Simple question, but today I can't do anything.

Accepted Answer

Image Analyst
Image Analyst on 5 May 2020
Try using the brackets trick to extract the values out of the fields and concatenate into a vector:
allValues = [yourStructure.yourFieldName]
maxValue = max(allValues)
If your field is a row vector instead of a scalar, use vertcat():
allValues = vertcat(yourStructure.yourFieldName)
columnMaxValues = max(allValues, 1) % Max going down all the columns
rowMaxValues = max(allValues, 2) % Max going across all the rows.

More Answers (2)

Johannes Rebling
Johannes Rebling on 5 May 2020
Edited: Johannes Rebling on 5 May 2020
Tracy on 27 Sep 2023
Thank you! had thesame problem and surprisingly this works perfectly. cant beleive it was such a simple fix.
Image Analyst
Image Analyst on 27 Sep 2023
@Tracy yes, and it could be simpler. Note in my Accepted Answer above I don't use (:) because it's unnecessary if the values are simply scalars. And you will want to assign the output of max() to some variable (like I did above). Otherwise it's just basically thrown away and you can't use it. Above I essentially did
maxValue = max([yourStructure.yourFieldName])
Or for his code...
Struct(1).yourData = 1;
Struct(2).yourData = 2;
maxValue = max([Struct.yourData]) % No (:) needed. And save the max value for use in subsequent code.

Sign in to comment.

Peter O
Peter O on 5 May 2020
Edited: Peter O on 5 May 2020
If I'm understanding correctly, you have a struct array, s, of size 1x30, with a single field (let's call it x). Something like
s(1).x= 10
s(2).x = 11
s(30).x = 1.123
Use arrayfun to access the field of each struct in the array. Because there's a uniform output, you'll get a vector output. Then take the max:
max(arrayfun(@(z) z.x, s))
Alternatively, use the colon operator to access each element, turn it into a single array using the brackets, and then take the max:
Hope this helps!
  1 Comment
Image Analyst
Image Analyst on 5 May 2020
Like I showed in my answer, the (:) is unneeded.

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!