how to find the number of occurances

i have a matrix x=[1 1 1 1 2 2 1 1 3 3 ]

i want the output to be x1=[1 2 1 3] and y1=[4 2 2 2]

x1 should have the reduced number from input and x2 should be the number of ocurances

[per isakson]

Search the File Exchange for run length encoding

Answer 1

[madhan ravi]

x=[1 1 1 1 2 2 1 1 3 3];
idx=logical([diff(x)~=0,1]);
x1=x(idx)
yy=find(idx);
yyy=diff(find(idx));
y1=[yy(1) yyy]
x2=histc(x,unique(x))  % number of occurences
unique_numbers_and_their_occurences=[unique(x); histc(x,unique(x))].' %bonus

Gives:

x1 =

     1     2     1     3


y1 =

     4     2     2     2


x2 =

     6     2     2

unique_numbers_and_their_occurences =

     1     6
     2     2
     3     2 

[johnson saldanha]

they are column vectors. not row vectors. whats the correction

[madhan ravi]

x=x.' % just transpose x at the beginning
%or
x=[1;1;1;1;2;2;1;1;3;3];
idx=logical([diff(x)~=0;1]);
x1=x(idx)
yy=find(idx);
yyy=diff(find(idx));
y1=[yy(1);yyy(2:end)]
x2=histc(x,unique(x))  % number of occurences
unique_numbers_and_their_occurences=[unique(x) histc(x,unique(x))]

[johnson saldanha]

why are the number of columns of x1 and y1 not the same

[madhan ravi]

Try this I corrected the mistake:

x=[1;1;1;1;2;2;1;1;3;3];
idx=logical([diff(x)~=0;1]);
x1=x(idx)
yy=find(idx);
yyy=diff(find(idx));
y1=[yy(1);yyy]
x2=histc(x,unique(x))  % number of occurences
unique_numbers_and_their_occurences=[unique(x) histc(x,unique(x))]

Gives :

>> COMMUNITY

x1 =

     1
     2
     1
     3


y1 =

     4
     2
     2
     2


x2 =

     6
     2
     2


unique_numbers_and_their_occurences =

     1     6
     2     2
     3     2

>>