MATLAB Central Newsreader - Sort and revert

Sort and revert

fas — Thu, 13 Nov 2008 05:53:54 -0500

Hi,
I have a vector which I have sorted B=sort(A); Now after changing the
10 values on either end I would like to take the vector back to A.
B=sort(A);
B(1:10)=20;
B(90:100)=70;
Now I want to transform B->A so that the indexing is same of what my A
was.

Since its an image I have to revert back to same indexing of vector
only with changed values that I did after sorting.

Any idea ?

Re: Sort and revert

Ning — Thu, 13 Nov 2008 06:33:02 -0500

fas <faisalmufti@gmail.com> wrote in message <195e56e8-c7b9-49b3-839f-fd0468067e86@35g2000pry.googlegroups.com>...
> Hi,
> I have a vector which I have sorted B=sort(A); Now after changing the
> 10 values on either end I would like to take the vector back to A.
> B=sort(A);
> B(1:10)=20;
> B(90:100)=70;
> Now I want to transform B->A so that the indexing is same of what my A
> was.
>
> Since its an image I have to revert back to same indexing of vector
> only with changed values that I did after sorting.
>
> Any idea ?
That's easy. Try help sub2ind first, after you sorted and changed the vector, try help ind2sub.
May it helps.

Re: Sort and revert

fas — Thu, 13 Nov 2008 06:46:35 -0500

On Nov 13, 5:33=A0pm, "Ning" <ning.ro...@gmail.com> wrote:
> fas <faisalmu...@gmail.com> wrote in message <195e56e8-c7b9-49b3-839f-fd0=
468067...@35g2000pry.googlegroups.com>...
> > Hi,
> > I have a vector which I have sorted B=3Dsort(A); Now after changing the
> > 10 values on either end I would like to take the vector back to A.
> > B=3Dsort(A);
> > B(1:10)=3D20;
> > B(90:100)=3D70;
> > Now I want to transform B->A so that the indexing is same of what my A
> > was.
>
> > Since its an image I have to revert back to same indexing of vector
> > only with changed values that I did after sorting.
>
> > Any idea ?
>
> That's easy. Try help sub2ind first, after you sorted and changed the vec=
tor, try help ind2sub.
> May it helps.

Sorry I could not work sub2ind for my case :(

Re: Sort and revert

fas — Thu, 13 Nov 2008 06:48:49 -0500

Re: Sort and revert

Roger Stafford — Thu, 13 Nov 2008 07:06:09 -0500

fas <faisalmufti@gmail.com> wrote in message <195e56e8-c7b9-49b3-839f-fd0468067e86@35g2000pry.googlegroups.com>...
> Hi,
> I have a vector which I have sorted B=sort(A); Now after changing the
> 10 values on either end I would like to take the vector back to A.
> B=sort(A);
> B(1:10)=20;
> B(90:100)=70;
> Now I want to transform B->A so that the indexing is same of what my A
> was.
>
> Since its an image I have to revert back to same indexing of vector
> only with changed values that I did after sorting.
>
> Any idea ?

Use the second output argument of 'sort':

[B,p] = sort(A);
B(1:10) = 20;
B(90:100) = 70;
A(p) = B;

Roger Stafford

Re: Sort and revert

Roger Stafford — Thu, 13 Nov 2008 13:15:03 -0500

"Roger Stafford" <ellieandrogerxyzzy@mindspring.com.invalid> wrote in message <gfgjl1$r0c$1@fred.mathworks.com>...
> fas <faisalmufti@gmail.com> wrote in message <195e56e8-c7b9-49b3-839f-fd0468067e86@35g2000pry.googlegroups.com>...
> > Hi,
> > I have a vector which I have sorted B=sort(A); Now after changing the
> > 10 values on either end I would like to take the vector back to A.
> > B=sort(A);
> > B(1:10)=20;
> > B(90:100)=70;
> > Now I want to transform B->A so that the indexing is same of what my A
> > was.
> >
> > Since its an image I have to revert back to same indexing of vector
> > only with changed values that I did after sorting.
> >
> > Any idea ?
>
> Use the second output argument of 'sort':
>
> [B,p] = sort(A);
> B(1:10) = 20;
> B(90:100) = 70;
> A(p) = B;
>
> Roger Stafford

Or you could do this instead:

[p,p] = sort(A);
A(p(1:10)) = 20;
A(p(90:100)) = 70;

Roger Stafford

Re: Sort and revert

fas — Sun, 16 Nov 2008 01:39:24 -0500

On Nov 14, 12:15=A0am, "Roger Stafford"
<ellieandrogerxy...@mindspring.com.invalid> wrote:
> "Roger Stafford" <ellieandrogerxy...@mindspring.com.invalid> wrote in mes=
sage <gfgjl1$r0...@fred.mathworks.com>...
> > fas <faisalmu...@gmail.com> wrote in message <195e56e8-c7b9-49b3-839f-f=
d0468067...@35g2000pry.googlegroups.com>...
> > > Hi,
> > > I have a vector which I have sorted B=3Dsort(A); Now after changing t=
he
> > > 10 values on either end I would like to take the vector back to A.
> > > B=3Dsort(A);
> > > B(1:10)=3D20;
> > > B(90:100)=3D70;
> > > Now I want to transform B->A so that the indexing is same of what my =
A
> > > was.
>
> > > Since its an image I have to revert back to same indexing of vector
> > > only with changed values that I did after sorting.
>
> > > Any idea ?
>
> > =A0 Use the second output argument of 'sort':
>
> > =A0[B,p] =3D sort(A);
> > =A0B(1:10) =3D 20;
> > =A0B(90:100) =3D 70;
> > =A0A(p) =3D B;
>
> > Roger Stafford
>
> =A0 Or you could do this instead:
>
> =A0[p,p] =3D sort(A);
> =A0A(p(1:10)) =3D 20;
> =A0A(p(90:100)) =3D 70;
>
> Roger Stafford

Thanks a lot Roger!