Comparing 2 columns of a matrix

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I want to compare 2 columns of my matrix as shown below:
For example, I have the number 4 in the first column occurring thrice. I need to compare it's corresponding values in column 2 and obtain the minimum value among them. I then need to store that value in another matrix.
Could someone suggest me a way to get this desired result.
Thanks and regards

Accepted Answer

Star Strider
Star Strider on 23 Feb 2019
Try this (using the accumarray (link) function):
A = [randi(10, 20, 1) rand(20,1)] % Create Data
[A1u,~,idx] = unique(A(:,1)); % Unique Values & Indices
MinVals = accumarray(idx, A(:,2), [], @(x)min(x)); % Find Minimum Of Each
Result = [A1u, MinVals] % Desired Result
Use your own matrix for ‘A’.
Star Strider
Star Strider on 24 Feb 2019
As always, my pleasure.

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More Answers (1)

Image Analyst
Image Analyst on 23 Feb 2019
You can do this easily with unique() and histogram() or histcounts(). Since you didn't include your data in a way that's easy for us to code up, I assume you'd prefer to do it yourself, so give it a try. If you run into problems, attach your data and explain the problem(s).
  1 Comment
Gautami Golani
Gautami Golani on 23 Feb 2019
My code is as shown below. It's just a part of my entire program.
I'm trying to compare all the 3 values of the number 4.0000 in column 2 and find out the min of them.
Example: For 4.000 the corresponding values in column 2 are 0.0042, 0.0028 and 0.0015.
So my new matrix should have the min of these 3, which is 0.0015.

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