How to filter data in a variable based on its value

Question

Nom 2020-5-7

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/523831-how-to-filter-data-in-a-variable-based-on-its-value

评论： Star Strider 2020-5-7

采纳的回答： Star Strider

在 MATLAB Online 中打开

Hello,

I have one 100 by 3 array which contains random values from 0 to 1000

I wanted to filter the data in a new array so that only values above 500 are shown.

To do this I did

A = randi([0 1000],100,3) %Generates random numbers from 0 to 1000 in a 100by3 array
A(A>500) %This is the area I need help

In the code above, A(A>500) only shows me values from the first column of A which are greater than 500.

How can I extend this so that A(A>500) will generate a x by 3 array?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Star Strider 2020-5-7

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/523831-how-to-filter-data-in-a-variable-based-on-its-value#answer_431053

在 MATLAB Online 中打开

This will set the elements that are less than or equal to 500 to 0:

A = A.*(A>500);

It preserves the structure of ‘A’.

2 个评论
显示无隐藏无

Nom 2020-5-7

在 MATLAB Online 中打开

Thank you so much!

I spent way too long on this, I was attempting to do it on cellfun as well but wasn't able to get that working.

A = cellfun(@(x) A>500,A,'UniformOutput',0);

Just out of cursiosity would you happen to know the cellfun equivalent? (Assuming A is a cell of course)

Star Strider 2020-5-7

在 MATLAB Online 中打开

Try this:

A = randi([0 1000],100,3); %Generates random numbers from 0 to 1000 in a 100by3 array
% A(A>500) %This is the area I need help
Ac = mat2cell(A, ones(1,size(A,1)), ones(size(A,2),1));         % Create Cell Array
ix = cell2mat(cellfun(@(x)x>500,Ac, 'Uni',0));                  % Logical Index Matrix
Ac(~ix) = {[]};                                                 % Output

My intent was to have the elements that did not meet the criterion be empty [] elements. They are 0 instead. That may reflect a difference in how cell arrays are handled in R2020a.

请先登录，再进行评论。