Thread Subject: Help with a tricky Vector Problem

Hi


I am trying to manipulate a large vector without a loop.

For example
a = [1:10], b = [1 2 4 5 8 10]

a b

1 1
2 2
3 4
4 5
5 8
6 10
7
8
9
10

I want all the elements of 'a' to be in in 'b'. At the end I want 'b' to be b= 1:10

1. both vectors are already sorted
2. any element of 'a' not in 'b', should be added to b, and the index noted.
3. for the example above, first index of 'a' is 1, it is in 'b',next, second index of 'a' is 2, it is in 'b'.
4.third index of 'a' is 3, not in 'b', hence 3 will be added to b, and the index noted (3).
5. Note now, that b is now [1 2 3 4 5 8 10].
6 Next,'a' at index 4 is 4, which is also in index 4 of b, then continue to index 5 of 'a' e t c.

at the end b = [1:10], index = 3,6,7,9.

  

"ade77 " <ade100a@gmail.com> wrote in message <hdk2vr$i5k$1@fred.mathworks.com>...
> Hi
>
>
> I am trying to manipulate a large vector without a loop.
>
> For example
> a = [1:10], b = [1 2 4 5 8 10]
>
> a b
>
> 1 1
> 2 2
> 3 4
> 4 5
> 5 8
> 6 10
> 7
> 8
> 9
> 10
>
> I want all the elements of 'a' to be in in 'b'. At the end I want 'b' to be b= 1:10
>
> 1. both vectors are already sorted
> 2. any element of 'a' not in 'b', should be added to b, and the index noted.
> 3. for the example above, first index of 'a' is 1, it is in 'b',next, second index of 'a' is 2, it is in 'b'.
> 4.third index of 'a' is 3, not in 'b', hence 3 will be added to b, and the index noted (3).
> 5. Note now, that b is now [1 2 3 4 5 8 10].
> 6 Next,'a' at index 4 is 4, which is also in index 4 of b, then continue to index 5 of 'a' e t c.
>
> at the end b = [1:10], index = 3,6,7,9.
>
>

Actually not that tricky.
a=[1:10];
 b = [1 2 4 5 8 10];
NewVec=sort(unique([a b]) );
IndexVec=find(~ismember(NewVec, b) );
Regards Matt

index=setdiff(a,b);
b=union(a,b);

"Matt " <xys@whatever.com> wrote in message <hdkalg$gjc$1@fred.mathworks.com>...
>
> index=setdiff(a,b);
> b=union(a,b);

Thank you Matt