How to save specified data from a matrix?

1 次查看(过去 30 天)
hello, everyone.
I am wondering how can I delete specified data from a data matrix. For example, if I have a matix like this:
m=rand(100,5);
How can I save a matrix that satisfy this : for each row, each element is smaller than a specified number such as 0.200.
I know I can use indice, eg. ind=find(m(:,2:5)< 0.2)
but I can't save it by using m1=m(ind,:)
I guess the problem is the number of rows is changing when I use m1=m(ind,:).
does anyone know how can i achieve this?
Thanks.

采纳的回答

Walter Roberson
Walter Roberson 2012-8-27
Your line
ind=find(m(:,2:5)< 0.2)
is not correct. You need
ind=find(all(m(:,2:5)< 0.2,2))
  8 个评论
Lei
Lei 2012-8-27
编辑:Lei 2012-8-27
I see what you mean now!!! Thx a lot. But what if I want save the data meets this criteria: for each row, any of the element in this row is bigger than a number (0.2), then I save the data. Thats why I used this ind=find(m(:,2:5)< 0.2);. In this case, I cant save the data by using m1=m(ind,:);. What you code was doing is that all of the elements in that row are smaller than 0.2 Do you have any idea how can I do this???
Lei
Lei 2012-8-27
probaably ind=find(any(M(:,2:5)>54,2));

请先登录,再进行评论。

更多回答(1 个)

Babak
Babak 2012-8-27
if your matrix m is 100 by 1, you can do this:
m(m<0.2)
gives you a new matrix that is smaller or equal size to the original matrix.
For a 100 by 5 m, I think you can write a for loop on the different columns of m,
a = m<.2;
for j=1:5
m(a(:,j)) % gives you the elemets of m(:,j) that are less than 0.2
end
  1 个评论
Lei
Lei 2012-8-27
hello Babak, Thx for your help,I tried your code. but it seems does not work.

请先登录,再进行评论。

类别

Help CenterFile Exchange 中查找有关 Loops and Conditional Statements 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