- loop over the vectors backwards
- collect an index (e.g. a logical vector) and remove the elements at once after the loop
Unable to remove elements from array and I don't know why
3 views (last 30 days)
Show older comments
I have been using matlab for a few years but I just am having one of those days and cannot figure out what is going on here. I have two arbitrary arrays, I iterate and take the distance of each point. If that distance is below 10, I want to remove those elements from the array, therefore shortening the array. The error I'm getting is in the asteriks.
************************************
A null assignment can have only one non-colon index.
Error in LoopTesting (line 10)
x(1,i)=[];
***********************************
Please explain to me why this is happening. Thank you!
y = [1 2 3 4 5 6 7 7 8 8 9 9 10 10];
x = [4 5 6 1 2 3 4 5 6 7 8 8 9 10];
xc = 15;
yc = 15;
for i=1:length(x)
d=sqrt(((xc-x(i))^2)+(yc-y(i))^2);
if d < 10
x(1,i)=[];
y(1,i)=[];
end
end
length(x)
length(y)
1 Comment
Stephen23
on 12 Jan 2021
The problem is that once you remove an element the vector is shorter, but your loop still attempts to index into elements that no longer exist (because you have just shortened the vector). To avoid this either:
Answers (1)
Fangjun Jiang
on 12 Jan 2021
Edited: Fangjun Jiang
on 12 Jan 2021
Do the loop backward should resolve the problem. I hope you would understand the reason.
for i=length(x):-1:1
Also, better to use x(i)=[] since it is a vector.
See Also
Categories
Find more on Matrix Indexing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!