How to sum all positive values in each row in matrix?

Hello.

I have a 8760x10 matrix where i want to sum all positive numbers in each row seperatly to yield a new 8760x1 vector with the sum of all positive values from each row. normally if i would do it on a single vector then i would just use:

sum(d(d>0))

but i dont know how to do it within a loop and for many rows

Here is what i got so far:

for i = 1:n
    
    central(i)      = sum(prod((i),(1:6)))+sum(prod((i),(12:17)))+sum(prod((i),(20:25)))+sum(prod((i),(93:100)));
    decentral(i)    = sum(prod((i),(7:11)))+sum(prod((i),(18:19)))+sum(prod((i),(26:92)));
    solar(i)        = sum(renew((i),(1:12)));
    hydro(i)        = renew(i,13);
    wind(i)         = sum(renew((i),(14:78)));
    netimport(i)    = sum(inter((i),(1:7)))+sum(inter((i),(9:10)));
    
    if netimport(i) < 0
        netimport(i) = 0;
        
    elseif netimport(i) > 0
  
        totalimport(i) = sum(inter(i)(inter(i)>0)); % this is the line i dont know how to do. it should be able to sum all positive numbers in all 8760 seperatly.
        
        % another idea that i have had was:
        
        totalimport(i) = sum(inter((i),(1:10))(inter((i),(1:10))>0));
        
        

Anybody that can help? :)

Answer 1

[Torsten]

sum(max(A,0),2)

Answer 2

[Image Analyst]

sum(d(d>0))

would sum all values in the matrix and give you a single number, NOT the sum of rows. You'd want

dCopy = d;
dCopy(d <= 0) = 0;
% Sum along columns to give a sum for every row.
columnVectorSums = sum(dCopy, 2); 

Why would you want to do it via a for loop?

Answer 3

[tmarske]

Firstly, I assume that prod is either a function you have written or a variable you created? If so it's overwriting the matlab builtin function prod. This is something you generally want to avoid doing and I'd strongly suggest you pick a different name for this function/variable.

Returning to your question, you can do:

sum(max(d, 0), 2)

for example:

>> aa = magic(6)-15

aa =

    20   -14    -9    11     4     9
   -12    17    -8     6     8    10
    16    -6   -13     7    12     5
    -7    13    18     2    -5     0
    15   -10    19    -3    -1     1
   -11    21    14    -2     3    -4

>> sum(max(aa, 0), 2)

ans =

    44
    41
    40
    33
    35
    38