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From: ibrahim on 19 Apr 2010 13:44
Hey every one, I hope to help me with this one
i want to find the indices of a specific rang of numbers, for example
x= [20,10,4, 18, 16, 5, 2,17, 9, 13, 19, 15, 14, 7, 3, 11, 6, 12, 1, 8]
and i wanna to fin the indices of the numbers, for example, from 1:20
the ans y is
y=[19, 7, 15, 3, 6, 17, 14, 20, 9, 2, 16, 18, 10, 13, 12,5, 8, 4, 11, 1]

i made this code
for i=1:20
y=find(x==i,1);
end;

but this code takes a lot of time to execute, specially for large dimensions of x and large values of i

i need a script that do the same job but in much lower time

thanks!
From: Pekka Kumpulainen on 19 Apr 2010 13:57
"ibrahim " <ibrahim_elashry(a)yahoo.com> wrote in message <hqi4p5$a9c$1(a)fred.mathworks.com>...
> Hey every one, I hope to help me with this one
> i want to find the indices of a specific rang of numbers, for example
> x= [20,10,4, 18, 16, 5, 2,17, 9, 13, 19, 15, 14, 7, 3, 11, 6, 12, 1, 8]
> and i wanna to fin the indices of the numbers, for example, from 1:20
> the ans y is
> y=[19, 7, 15, 3, 6, 17, 14, 20, 9, 2, 16, 18, 10, 13, 12,5, 8, 4, 11, 1]
>
> i made this code
> for i=1:20
> y=find(x==i,1);
> end;
>
> but this code takes a lot of time to execute, specially for large dimensions of x and large values of i
>
> i need a script that do the same job but in much lower time
>
> thanks!

Like this?
>> [~,ind] = sort(x)

ind =

Columns 1 through 15

19 7 15 3 6 17 14 20 9 2 16 18 10 13 12

Columns 16 through 20

5 8 4 11 1
From: someone on 19 Apr 2010 13:57
"ibrahim " <ibrahim_elashry(a)yahoo.com> wrote in message <hqi4p5$a9c$1(a)fred.mathworks.com>...
> Hey every one, I hope to help me with this one
> i want to find the indices of a specific rang of numbers, for example
> x= [20,10,4, 18, 16, 5, 2,17, 9, 13, 19, 15, 14, 7, 3, 11, 6, 12, 1, 8]
> and i wanna to fin the indices of the numbers, for example, from 1:20
> the ans y is
> y=[19, 7, 15, 3, 6, 17, 14, 20, 9, 2, 16, 18, 10, 13, 12,5, 8, 4, 11, 1]
>
> i made this code
> for i=1:20
> y=find(x==i,1);
> end;
>
> but this code takes a lot of time to execute, specially for large dimensions of x and large values of i
>
> i need a script that do the same job but in much lower time
>
> thanks!

>> doc sort
>> x= [20,10,4, 18, 16, 5, 2,17, 9, 13, 19, 15, 14, 7, 3, 11, 6, 12, 1, 8];
>> [s,y] = sort(x);
>> y

y =

Columns 1 through 12

19 7 15 3 6 17 14 20 9 2 16 18

Columns 13 through 20

10 13 12 5 8 4 11 1
From: Matt Fig on 19 Apr 2010 13:57
[y,y] = sort(x);
From: ibrahim on 19 Apr 2010 14:27
"ibrahim " <ibrahim_elashry(a)yahoo.com> wrote in message <hqi4p5$a9c$1(a)fred.mathworks.com>...
> Hey every one, I hope to help me with this one
> i want to find the indices of a specific rang of numbers, for example
> x= [20,10,4, 18, 16, 5, 2,17, 9, 13, 19, 15, 14, 7, 3, 11, 6, 12, 1, 8]
> and i wanna to fin the indices of the numbers, for example, from 1:20
> the ans y is
> y=[19, 7, 15, 3, 6, 17, 14, 20, 9, 2, 16, 18, 10, 13, 12,5, 8, 4, 11, 1]
>
> i made this code
> for i=1:20
> y=find(x==i,1);
> end;
>
> but this code takes a lot of time to execute, specially for large dimensions of x and large values of i
>
> i need a script that do the same job but in much lower time
>
> thanks!

thank u every one.......... this was helpful
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