Removing duplicate elements & choose maximum row value of matrix

Hello,

I have an matrix, which have repeated values at row 8, I want to choose the row with maximum value in elements in column 4 and discard the rows with repeated value in column 8.

A= [1973 2 12 0.89518 1973 2 14 1468
1973 4 3 1.1867 1973 3 24 1903
1973 10 21 1.1006 1973 10 24 1307
1973 11 6 0.91814 1973 11 3 1913
1973 11 13 0.9313 1973 11 3 1913
1973 11 19 1.2501 1973 11 9 1618
1973 11 25 1.1185 1973 12 1 2953
1973 12 7 1.3553 1973 12 1 2953];

I would like to delete 4th & 7th row in this case. The desired output is:

1973 2 12 0.89518 1973 2 14 1468
1973 4 3 1.1867 1973 3 24 1903
1973 10 21 1.1006 1973 10 24 1307
1973 11 13 0.9313 1973 11 3 1913
1973 11 19 1.2501 1973 11 9 1618
1973 12 7 1.3553 1973 12 1 2953
Any help?

Answer 1

[Andrei Bobrov]

[~,~,c] = unique(A(:,end),'stable');
out = A(accumarray(c,(1:size(A,1))',[],@(x)x(max(A(x,4)) == A(x,4))),:);

[Poulomi Ganguli]

Thanks a bunch! It really works.

Answer 2

[KSSV]

Read about unique and max.

A = [1973 2 12 0.89518 1973 2 14 1468
     1973 4 3 1.1867 1973 3 24 1903
     1973 10 21 1.1006 1973 10 24 1307
     1973 11 6 0.91814 1973 11 3 1913
     1973 11 13 0.9313 1973 11 3 1913
     1973 11 19 1.2501 1973 11 9 1618
     1973 11 25 1.1185 1973 12 1 2953
     1973 12 7 1.3553 1973 12 1 2953];

[maxval,idx] = max(A(:,4)) ;

idx = find(A(:,8)==A(idx,8)) ;
A(idx(2:end),:) = []

[Poulomi Ganguli]

yea but it does not eliminate rows with element 1913?