eleminating data from a long vector

Hi all!

i have an index vector:

 %
  index=[id1;id2;id3.....idn]

and i have a long vector: A

i want to eleminate the elment of the vector a which have the index in index in this way:

 % 
A(id1:id1+30)=[]
A(id2:id2+30)=[]
.
.
.A(idn:idn+30)=[]

how could i write this in matlab in a compact manner?

thank you

[Walter Roberson]

Are you certain this is what you want to do? After the first removal, everything from id1+30 onward in the vector would "fall down" 31 places. Does id2 take that renumbering into account?

Answer 1

[Azzi Abdelmalek]

A=rand(1,1000);   % Example
index=[10 100 500]
idx=arrayfun(@(x) x:x+30,index,'un',0);
A(cell2mat(idx))=[]

[Walter Roberson]

This is not equivalent to the original sequence in that the original sequence does not delete id2:id2+30 until after id1:id1+30 are gone, so in absolute locations it might need to add 31 more for the 2nd index, 62 for the 3rd, and so on... depending on the sort order of the indices.

[Azzi Abdelmalek]

I don't think that what he meant by the sequence. I guess he want to remove them at the same time.

Answer 2

[Andrei Bobrov]

A=1:1000;   % Example
index=[10 100 500];
n = 30;
A(bsxfun(@plus,index,(0:n-1)'))=[];

[Walter Roberson]

Should either be n=31 or run from 0:n instead of 0:n-1 as the original question asks to delete id1:id1+30 which is 31 locations.

[Jan]

But in general this method is faster than the arrayfun and cell2mat approach.

[Rica]

Thank you all