How to compare each four rows by each other?

Hello,

Suppose we have 8 rows where each element in a row is either zero or one. I want to compare rows to count differences in this way:

row1 with row2 ; row1 with row 3; row1 with row4; row2 with rows 3; row2 with row4; row3 with row4.

So how can I do that in repetition manner to repeat doing that for row5,6,7, and 8 together. note that the number of different elements between any two rows should be stored in a matrix where in our case here we should have 6 rows in the differences matrix where each row store the number of differences between two rows in the main matrix.

Regards,

Answer 1

[Star Strider]

If you have the Statistics and Machine Learning Toolbox, use the pdist (link) function, specifying the 'hamming' distance measure:

data = randi([0 1], 8, 5)                               % Create Data
d = pdist(data, 'hamming');
DistancesP = squareform(d)                              % Percentage Differences
DistancesA = squareform(d) * size(data,2)               % Number Of Elements That Differ

produces:

data =
     1     1     1     1     0
     0     0     1     0     0
     0     0     1     0     0
     0     0     0     1     0
     0     1     1     1     1
     0     0     0     0     1
     1     0     1     1     1
     1     0     0     1     1

DistancesA =
     0     3     3     3     2     5     2     3
     3     0     0     2     3     2     3     4
     3     0     0     2     3     2     3     4
     3     2     2     0     3     2     3     2
     2     3     3     3     0     3     2     3
     5     2     2     2     3     0     3     2
     2     3     3     3     2     3     0     1
     3     4     4     2     3     2     1     0

Answer 2

[ahmed nebli]

i prpose this algorithm: u define a variable m=4, and n=1, n is the number of the row, each time u search for your diffrences between rows (+-n), then n=n+1 and u compare rows (m-n) and n=n+1, and so on ... each time u store it in an external matrix A ( like u said), after that m=m+4 and u repeat the loop