MATLAB: Matrix index is out of range for deletion and I cant figure it out

errorfor loopmatrix indexout of range

I am getting the error "Matrix index is out of range for deletion". What I am trying to accomplish is: where ever there is a 0 in f…..i want to delete that row number from g.
g =
1 1 1 1
2 2 2 2
3 3 3 3
4 4 4 4
5 5 5 5
f =
1 1 0 1 0
>> for j= 1:numel(f)
if f(j)==0
g(j,:)=[]
end
end
g =
1 1 1 1
2 2 2 2
4 4 4 4
5 5 5 5
Matrix index is out of range for deletion.
The output should be g without the 3rd and 5th row.
g=[1 1 1 1; 2 2 2 2; 4 4 4 4]

Best Answer

Suppose you delete row 4. What was in row 5 "falls down" to row 4,what was in 6 falls to 5, and so on. If you had a request to delete row 6 then in order to delete it now, you would have to delete what is now row 5, because 6 fell to 5.
It is possible to work with a running total of the number you have deleted to figure out the current index of a given row.
However it is far easier to simply loop backwards. Delete from highest row number first: anything that falls down will be something you already know should not be deleted.
Or you could just vectorize the entire loop:
g(f==0,:) = [] ;
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