MATLAB: Index of element to remove exceeds matrix dimensions.

Question

In my code x tends to change from 1 to 7. Here I took a sample value as 4. I want to delete the array element, if it has less than 0 or greater than 8 otherwise save the value in the array. xplus is an 1-D array. xplus maximum value will be 7 values. I tried this code it is getting error as

ERROR: Index of element to remove exceeds matrix dimensions.

Error in deletearraytest (line 5) xplus(x1)=[];

and workspace variable x=4 , x1=7, xplus=[5;6;7;8;0]

Here is my code x=4; xplus=zeros(7,1); for x1=1:7 if((x+x1<=0)||(x+x1>8)) xplus(x1)=[]; else xplus(x1)=x+x1; end end

I have check the solutions of many links but, I cant understand the mistake I did. Many people said that when we are going to delete the array element, it not going to be previous size. I need more explanation in that and solve my problem. I am amateur matlab user. Help needed. Thanks in advance.

Answer 1

Because you're removing elements as you go, your array gets shorter, and your fixed index (1:7) can go out of bounds.

This is exactly what is happening when you have:

x1=7, xplus=[5;6;7;8;0]; xplus(x1)=[];

You're trying to remove the 7th element, when the array only has 5 elements in it.

A better way of accomplishing what you're doing is with logical indexing;

xplus(xplus < 0 | xplus > 8) = [];

which finds the elements of x < 0 or > 8 and removes them.