# Remove zeros from a vector from a specific position

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Commented: the cyclist on 18 Aug 2023
Hello, I have the following vector as example:
X=[0, 0; 0.02, 2.3;0.04, 0.4; 0, 0; 0.06, 2.5; 0.08, 3.6; 0, 0; 0.10, 2.5]
I want to remove the zeros and I only want to keep the zeros at the beginning and obtain the following matrix:
X=[0, 0; 0.02, 2.3;0.04, 0.4; 0.06, 2.5; 0.08, 3.6; 0.10, 2.5]
I know this option
X( all(~X,2), : ) = [];
which eliminates all the zeros and then I can add the zeros again at the beggining using
X=vertcat([0 0],X);
but there must be a direct way to do it. I would appreciate the help.
##### 2 CommentsShow NoneHide None
the cyclist on 18 Aug 2023
Will there always be at least one row of zeros at the beginning?
If so, will there always be exactly one row of zeros at the beginning?
Yes, there will be always zeros at the beginning.

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### Accepted Answer

Bruno Luong on 18 Aug 2023
remove = all(~X,2);
remove(1) = false;
X(remove,:) = [];
##### 6 CommentsShow 4 older commentsHide 4 older comments
THANK YOU VERY MUCH. :).
the cyclist on 18 Aug 2023
FYI, this solution will not work if there are multiple rows of leading zeros to keep. (That's why I asked if there was always exactly one row of leading zeros.) For example,
X = [0, 0;
0, 0;
2, 3;
5, 7;
0, 0];
X([false;all(~X(2:end,:),2)],:)=[]
X = 3×2
0 0 2 3 5 7

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