How to Remove Elements in a Matrix Less than a Threshold?
显示 更早的评论
Hi,
I have a 3000 x 3000 matrix and want to remove all elements inside the matrix that are less than a specific value, .5 for example.
How would I go about this?
Here's what I have so far but it doesn't seem to work:
function y = highestValues(a,b)
% a is the matrix
% b is the threshold value
[sortedValues,~] = sort(a,1,'descend');
exclude = sortedValues < b;
sortedValues(exclude) = [];
highestValue = sortedValues;
clearvars n sortedValues;
y = highestValue;
Thank you!
采纳的回答
Wayne King
2012-1-28
You can just do this: (removing all entries larger in absolute value than 2)
x = randn(10,10);
indices = find(abs(x)>2);
x(indices) = [];
But then x will be a vector and no longer a matrix of the same size you started with:
You can also do this:
x = randn(10,10);
indices = find(abs(x)>2);
x(indices) = NaN;
This will maintain your matrix.
3 个评论
Image Analyst
2012-9-26
编辑：Image Analyst
2012-9-26
It should be noted that the find() is not necessary.
Pierre Lonfat
2017-4-20
Do not work ! Matrix is not maintained ...
hbabar
2017-5-25
Ofcourse if you remove the elements, which was what was asked in the question, the matrix will not be mantained. If you just want to replace those values with a zero just do this:
A.*(A>Threshold))
更多回答（1 个）
Mohiuddin Ahmed
2012-9-26
I have a matrix like this : X =
5.1000 3.5000
4.9000 3.0000
4.7000 3.2000
4.6000 3.1000
5.0000 3.6000
5.4000 3.9000
4.6000 3.4000
5.0000 3.4000
4.4000 2.9000
4.9000 3.1000
I would like to delete an element from the matrix. how can I do that ?
3 个评论
Image Analyst
2012-9-26
You can't because the matrix would no longer be rectangular if you deleted just one element. You need to delete a whole row or whole column.
X(rowToDelete,:) = []; X(:, columnToDelete) = [];
Mohiuddin Ahmed
2012-10-31
well, if I want to delete an entire row from the matrix X? How can I do that ?
Marco Noll
2018-3-20
%lets assume we have some time
%and measurement data and want
%to remove any data that is out of range
%create some sample matrix
c= [1:6;100:105]
%create a mask matrix with all 1 where criteria matches
mask = c>102 & c<105
%use the second row of the mask to remove the data columns
c(:,mask(2,:))
%should work the same when transposing it
类别
在 帮助中心 和 File Exchange 中查找有关 Logical 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
