how to apply condition on multiple columns?
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I have a large data set that is unequal in every way so to get things done i have to apply condition on the element of the specific columns. E.g
1 1 234
1 1 234
1 1 180
1 2 345
1 2 674
.
.
.
8 1 453
8 1 678
8 2 478
8 2 345
8 2 345
.
.
.
31 21 456
31 22 452
31 22 345
31 23 670
31 23 567
31 23 456
what i want the programme to do is that check the value in column 1 if it equals 1 the check the value in column 2 if it equals 1 then take the mean of all the values in column 3 corresponding to column 2. similarly i want it to repeat for all the values in column 2 for 1st then all the other numbers in column 1 till last number in this case which is 31.
1 件のコメント
採用された回答
KSSV
2017 年 3 月 31 日
A = [1 1 234
1 1 234
1 1 180
1 2 345
1 2 674
8 1 453
8 1 678
8 2 478
8 2 345
8 2 345
31 21 456
31 22 452
31 22 345
31 23 670
31 23 567
31 23 456] ;
B = [1 1] ;
[idx,val] = ismember(A(:,1:2),B,'rows') ;
% get mean
iwant = sum(A(idx,3))/nnz(idx)
2 件のコメント
Stephen23
2017 年 3 月 31 日
See my answer for neater and more efficient solution without the inefficient loops and multiple ismember calls.
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