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arraysmatlabmatrixmatrix-indexing
CaptainProg
CaptainProg

Reputation: 5690

MATLAB: Select all of an array EXCEPT in given ranges

I'd like to perform metrics on the contents of an array that do NOT fall within certain ranges.

For example, I have an array with 1000 rows and 2 columns. I'd like to perform a mean() calculation on all the elements in one column (let's say column #2) that don't fall in rows 50-150, 250-300, 400-700 and 900-950.

Thus, the mean should be calculated based on rows 1-49, 151-249, 301-399, 701-899 and 951-1000.

Any ideas how to go about this?

Edit: I should point out that those items which are included will change each time the program is run. Therefore, I can't just hard-code the inclusions in; they need to be worked out based on the exclusions.

Upvotes: 3

Views: 9636

Answers (2)

nrz
nrz

Reputation: 10560

You can define the exclusion ranges and then use logical addressing:

LowerLimit1 = 1;
UpperLimit1 = 50;

LowerLimit2 = 151;
UpperLimit2 = 249;

LowerLimit3 = 301;
UpperLimit3 = 399;

LowerLimit4 = 701;
UpperLimit4 = 899;

LowerLimit5 = 951;
UpperLimit5 = 1000;

MyVector = MyMatrix(:,2);

MeanValue = mean(MyVector(~(MyVector > LowerLimit1 & MyVector < UpperLimit1) | (MyVector > LowerLimit2 & MyVector < UpperLimit2) |  (MyVector > LowerLimit3 & MyVector < UpperLimit3)  | (MyVector > LowerLimit4 & MyVector < UpperLimit4) | (MyVector > LowerLimit5 & MyVector < UpperLimit5)));

Upvotes: 0

Amro
Amro

Reputation: 124563

How about:

M = rand(1000,2);
idx = setdiff(1:size(M,1), [50:150, 250:300, 400:700, 900:950]);

MM = M(idx,:)

Now apply any function to the filtered matrix:

mean(MM,1)

Upvotes: 6

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