sorting and summing through data

hello please

I have the following data

for example T =

Drag Class

1 positive

3 positive

5 negative

7 positive

8 negative

6 positive

9 negative

2 positive

5 negative

9 negative

I want to write a code which will enable me to do the following computation

sort the data randomly

then when K = 1

k = 1 ( lowest positive / lowest negative) down the column

K = 2 ( lowest (positive ) + next lowest (positive) )/ (lowest ( negative) + next lowest ( negative) ) down the column till the end

K = 3 ( lowest ( positive) + next lowest ( positive) + next lowest ( positive) ) / ( lowest ( negative) + next lowest ( negative ) + next lowest ( negative)) down the column

This is done using if and conditional statement

Stop if no lowest number cannot be added to the sum anymore

Thanks in advance

Tino

[KALYAN ACHARJYA]

Be specific? Consider simpler example for better illustrations.

[Tino]

Ok thanks for your swift response let me break it down. I have a table that have data and a label. 1 pos 2 neg 5 neg 6 pos 6 pos 7 neg

Down to n numbers How do I write the code For example The lowest 2 numbers for pos are 1 and 6 The lowest 2 numbers for neg 2 and 5

Then the computation = (1+6)/(2+5) =7/7 =1 Thanks in advance

Tino

Answer 1

[Raghunandan V]

Hi,

I managed to solve the question. Please review and update

% positive is of class 1 and negetive is class 0 (just for ease of code)
A = [1 1; 3 1; 5 0; 7 1; 8 0; 6 1; 9 0; 2 1; 5 0; 9 0];
A_positive = A(A(:, 2) == 1);
A_negetive = A(A(:,2) == 0);
A_positive = sort(A_positive);
A_negetive = sort(A_negetive);
%get the length of positive and negetive numbers and len is taken as least of the both lengths
len = min(numel(A_positive), numel(A_negetive));
result = zeros(len,1);
for k = 1: len
    result(k) = sum(A_positive(1:k))/sum(A_negetive(1:k));
end
result

if you want for only particular value of k. then remove the for loop and give specific value of k.

Regards,

Raghunandan V

[Tino]

Thanks for the answer Raghunandan V

Do you know how to convert column positive and negative to 1 and 0 without having to do it manually.

Thanks for your help in advance

Regards

Tino

[Raghunandan V]

What is the format of the data?

1. Is it excel?

If yes, you can use find and replace the data in excel itself.

2. was it created by matlab?

if yes, then check the code and replace the string 'positive' and 'negetive' by 0 and 1