MATLAB Central Newsreader - Reversing a row matrix

Reversing a row matrix

Emeka Obe — Fri, 10 Oct 2008 14:56:03 -0400

Hi All,

I need to reverse a matrix as follows:
If x=[1 3 8 20 100 121],

how do I get a matrix

y=[121 100 20 8 3 1]

An answer is needed, please.

Emeka

Re: Reversing a row matrix

tpl@eng.cam.ac.uk (Tim Love) — Fri, 10 Oct 2008 15:00:11 -0400

"Emeka Obe" <obeway@gmail.com> writes:

>Hi All,

>I need to reverse a matrix as follows:
fliplr

Re: Reversing a row matrix

Walter Roberson — Fri, 10 Oct 2008 15:10:14 -0400

Emeka Obe wrote:

> I need to reverse a matrix as follows:
> If x=[1 3 8 20 100 121],

> how do I get a matrix

> y=[121 100 20 8 3 1]

> An answer is needed, please.

r = randperm(length(x));
t1 = x(r);
[t2,t3] = sort(r,'descend');
y = t1(t3);

Re: Reversing a row matrix

Dan Hensley — Fri, 10 Oct 2008 16:24:00 -0400

Emeka Obe wrote:
> Hi All,
>
> I need to reverse a matrix as follows:
> If x=[1 3 8 20 100 121],
>
> how do I get a matrix
>
> y=[121 100 20 8 3 1]
>
> An answer is needed, please.
>
> Emeka

y=x(end:-1:1);

Dan

Re: Reversing a row matrix

swgillan — Sat, 11 Oct 2008 06:05:42 -0400

On Oct 10, 7:56=A0am, "Emeka Obe" <obe...@gmail.com> wrote:
> Hi All,
>
> I need to reverse a matrix as follows:
> If x=3D[1 3 8 20 100 121],
>
> how do I get a matrix
>
> y=3D[121 100 20 8 3 1]
>
> An answer is needed, please.
>
> Emeka

>> x=3D[1 3 8 20 100 121]

x =3D

1 3 8 20 100 121
>> y =3D fliplr(x)

y =3D

121 100 20 8 3 1

Hope that helps

Re: Reversing a row matrix

Muma Kaba — Sat, 23 May 2009 18:35:01 -0400

If you intend to flip an nxm matrix; proceed as follows:

%% flip a matrix vertically
Let A be an nxm matrix
B = size(A); %finds the number of rows and columns in the matrice

for i = 1:B(2); %for i = 1 to the number of columns
    for j = 1:B(1) %for j = 1 to the number of rows
        NEW_MAP(j,i)=[A((B(1)+1)-j,i)] %this simply flips the order of the row entries.
    end
end

Regards,

Muma
swgillan <swgillan@gmail.com> wrote in message <988983f9-5513-4057-b431-2fb44a707ca7@w39g2000prb.googlegroups.com>...
> On Oct 10, 7:56=A0am, "Emeka Obe" <obe...@gmail.com> wrote:
> > Hi All,
> >
> > I need to reverse a matrix as follows:
> > If x=3D[1 3 8 20 100 121],
> >
> > how do I get a matrix
> >
> > y=3D[121 100 20 8 3 1]
> >
> > An answer is needed, please.
> >
> > Emeka
>
> >> x=3D[1 3 8 20 100 121]
>
> x =3D
>
> 1 3 8 20 100 121
> >> y =3D fliplr(x)
>
> y =3D
>
> 121 100 20 8 3 1
>
> Hope that helps

Reversing a row matrix

Srikumar Murthy — Sat, 12 Sep 2009 13:25:04 -0400

y=flipdim(x,2)

see help flipdim.m for more info.

Srikumar

"Emeka Obe" <obeway@gmail.com> wrote in message <gcnqe3$s7h$1@fred.mathworks.com>...
> Hi All,
>
> I need to reverse a matrix as follows:
> If x=[1 3 8 20 100 121],
>
> how do I get a matrix
>
> y=[121 100 20 8 3 1]
>
> An answer is needed, please.
>
> Emeka