Removing elements from matrix

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Marin
Marin 2012-5-14
评论： Julia 2014-8-5
Hi everyone,
I was wonderning is there an easy way to remove some of the elemetts from matrix. I have a data array data(300x2) and I want to remove all rows that have the value in the second column smaller than 0.18.
I tried something like
data=data(data(:,2)<0.18);
and similar combinations but it doesn't work.
Thank you in advance for any advice you can offer.
  2 个评论
harsha
harsha 2014-8-5
hi
i have a 49x49 matrix and i want to delete the single element at center of the matrix.how can i do so?please help.
Julia
Julia 2014-8-5
What do you mean with delete? Set to 0? You can delete the row or the column containing the element, but you cannot create a hole in the middle of the matrix.

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采纳的回答

Andrei Bobrov
Andrei Bobrov 2012-5-14
data=data(data(:,2)>=0.18,:);
ADDED after Marin's comment
simple example
data1 =[...
2 3
5 8
10 3
4 6
6 7]
data2 =[...
9 2
10 2
6 3]
data1(ismember(data1(:),data2(:))) = nan
  1 个评论
Marin
Marin 2012-5-14
yeah, of course, now I see I could have solved it myself, but I've been too hasty. :)
thank you very much :)
another thing, if you can help me also.
if I have two data sets data1(300x2) and data2(50x2) and data2 contains elements that are in data1 (of course not all of them).
how do I create a matrix which has the data that is in data1 and not in data2 ?

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更多回答（1 个）

Marin
Marin 2012-5-15
Excellent. Thank you!

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