correlation coefficient between cells

I have a dataset stored in a similar manner to the follwing example:

clear all
Year = cell(1,4);
Year{1} = {'Y2007','Y2008','Y2009','Y2010','Y2011'};
Year{2} = {'Y2005','Y2006','Y2007','Y2008','Y2009'};
Year{3} = {'Y2009','Y2010','Y2011'};
Year{4} = {'Y2007','Y2008','Y2009','Y2010','Y2011'};

data = cell(1,4);
data{1} = {rand(26,1),rand(26,1),rand(26,1),rand(26,1),rand(26,1)};
data{2} = {rand(26,1),rand(26,1),rand(26,1),rand(26,1),rand(26,1)};
data{3} = {rand(26,1),rand(26,1),rand(26,1)};
data{4} = {rand(26,1),rand(26,1),rand(26,1),rand(26,1),rand(26,1)};
Where each cell in 'Year' represents the time where each measurement in 'data' was collected. For example, the first cell in Year ('Year{1}') contains the year where each measurements in 'data{1}' was collected so that data{1}{1} was collected in 'Y2007', data{1}{2} in 'Y2008'...and so on

I am now trying to find the correlation between each measurement with the corresponding (same year) measurement from the other locations. For example for the year 'Y2007' I would like to find the correlation between data{1}{1} and data{2}{3}, then data{1}{1} and data{4}{1}, and then data{2}{3} and data{4}{1} and so on for the remaining years, basically every possible combination of the years.

I know that the corrcoef command should be used to calculate the correlation, but I cannot seem to get to the stage where this is possible. Any advice would be much appreciated.

[Oleg Komarov]

Are data always the same length?

[Richard]

Yes all the same length.

Answer 1

[owr]

Something like this will help you find the index of where 'Y2007' shows in each cell of "Year":

K>> find( strcmp(Year{1},'Y2007') )

ans =

       1

K>> find( strcmp(Year{2},'Y2007') )

ans =

       3

Use these indicies to get the appropriate vecotrs out of "Data". Throw this in a loop over the unique values of Year and you should be all set:

   unique([Year{:}])

ans = 

      'Y2005'    'Y2006'    'Y2007'    'Y2008'    'Y2009'    'Y2010'    'Y2011'