MATLAB: How to extract a value from a sum in MATLAB

extract

i am trying to extract a certain value from a sum. for example, i have this 1+2+3+4+5 and from that i want to extract 2+3 how can this be done in MATLAB. This may seem like a basic question but I am new to MATLAB and have no idea what to do. I couldn't find anything on google or the MATLAB help

Best Answer

Do you always know the position of the terms you want to extract? Presumably, you have a vector in MATLAB and you are summing the elements of that vector, so you can just do a partial sum by using those indices.
   x = [1 2 3 4 5];
   sum(x(2:3))
If it's a very big vector and you're not sure the location of those elements, you can use logical indexing.
   sum(x(x>1 & x<4))
The above is simply saying, look inside x for all elements greater than 1 and less than 4 (and sum those)
Or is it more complicated than that?
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