Thread Subject: Simplify an array

dear matlab users

array=
[1] [2]
[3] [4]
[5] [7]
[6] [7]
[7] [8]
[9] [10]
[10][11]
now i'm trying to look if the numbers in the first column
growing with increment 1.
as result i want to display this array:
result=
[1] [2]
[3] [4]
[5] [8]
[9] [11]

for example:
three points
[5] [7]
[6] [7]
[7] [8]
i'm trying to simplify it to get the start and the end:
[5] [8]

how can i get this result-array?

thanx

Hi,

try this :

C={1 2
3 4
5 7
6 7
7 8
9 10
10 11}

idx=diff([-inf [C{:,1}]])==1;

C(idx,:)=[]

Jérôme

"Uwe Gallaun" <uwe.gallaun@stud.unileoben.ac.at> wrote in message
<fi0prq$r33$1@fred.mathworks.com>...
> dear matlab users
>
> array=
> [1] [2]
> [3] [4]
> [5] [7]
> [6] [7]
> [7] [8]
> [9] [10]
> [10][11]
> now i'm trying to look if the numbers in the first column
> growing with increment 1.
> as result i want to display this array:
> result=
> [1] [2]
> [3] [4]
> [5] [8]
> [9] [11]
>
> for example:
> three points
> [5] [7]
> [6] [7]
> [7] [8]
> i'm trying to simplify it to get the start and the end:
> [5] [8]
>
> how can i get this result-array?
>
> thanx
-------
  Is this what you want? Call 'a' be the original two-columned array.

 d = diff(a(:,1))~=1;
 r = [a([true;d],1),a([d;true],2)]; % The result

Roger Stafford

Jerome Briot <dutmatlab@yahoo.fr> wrote in message
<fi0uam$dlu$1@news.netfinity.fr>...
> Hi,
>
> try this :
>
> C={1 2
> 3 4
> 5 7
> 6 7
> 7 8
> 9 10
> 10 11}
>
> idx=diff([-inf [C{:,1}]])==1;
>
> C(idx,:)=[]
>
> Jérôme


with this code i can just delete those rows that are growing
+1.
if i have the array
    [ 1] [ 2]
    [ 3] [ 4]
    [ 5] [ 7]
    [ 6] [ 7]
    [ 7] [ 8]
    [ 9] [10]
    [10] [11]
i want to find which points belong to each other and write
the end- and startpoints in an array.
thats why i tried it with the growing of 1.
if it is 1 the next point belongs to the least, and if it's
not 0 it doesn't. in the end i should receive this array
    [1] [ 2]
    [3] [ 4]
    [5] [ 8]
    [9] [11]

how can i do that?