How to filter rows?
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I have a matrix like this
1 2 3 4 5 6 7 8
2 3 4 1 2 3 4 5
1 2 3 4 1 1 1 1
1 2 3 5 4 2 2 1
I want to separate those rows having first four entries as 1 2 3 4, as in above case I separate out row 1 and row three.
采纳的回答
Aletta Wilbrink
2018-2-9
编辑：Aletta Wilbrink
2018-2-9
Probably not the most efficient way, but this works
b = a(a(:,1)==1 & a(:,2) == 2 & a(:,3) == 3 & a(:,4) == 4,:)
Where a is the name of your matrix
2 个评论
Ammy
2018-2-9
Aletta Wilbrink
2018-2-9
编辑：Aletta Wilbrink
2018-2-9
Seeing Guillaume's answer, a better way is
b = a(all(a(:,1:4) == [1 2 3 4],2),:)
更多回答（1 个）
Guillaume
2018-2-9
%R2016b or later:
tokeep = all(A(:, 1:4) == [1 2 3 4], 2)
%earlier versions
tokeep = all(bsxfun(@eq, A(:, 1:4), [1 2 3 4]), 2)
%then
A(tokeep, :)
4 个评论
Les Beckham
2023-2-21
This question was about extracting elements from a matrix, not from a table containing cell arrays. You should start a new question and provide example data and what you want to do with the data, including any code you have tried (along with the results you expect and what you are getting instead, if applicable).
I suggest reading this first: TUTORIAL: how to ask a question (on Answers) and get a fast answer
Kurt
2023-2-22
The question is simply "How to filter rows?"
Anyway, I found the answer I needed. To filter rows of cells (not numerics) you can either read your data in as a table or convert your matrix to a table. Then use this one-liner:
output_data = input_data(table2array(input_data(:,col)) == "pattern",:);
where "col" is the column number you are filtering on.
There may be other approaches, but this works for me.
Les Beckham
2023-2-22
I'm glad you figured it out.
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