How do I sum the elements in a vector up to a specific value?

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Anna Pierce
Anna Pierce am 25 Okt. 2021
Bearbeitet: the cyclist am 25 Okt. 2021
I need to sum the numbers in an array up to the value 10. So with a function input of v=[2,3,2,2,1,3,1,10,3], I would not include 10 or any values after it in the sum. Below I have the function I am working with, I am currently getting an output of 18 instead of 14
function [prize]=sumPrize(v)
prize=0;
for i=1:length(v)<10
prize = prize + v(i);
end
end
  1 Kommentar
the cyclist
the cyclist am 25 Okt. 2021
Bearbeitet: the cyclist am 25 Okt. 2021
See my answer, but an explanation of why yours does not work is probably helpful.
Your loop does not do what you think it does. The line
for i=1:length(v)<10
is evaluated as follows:
  1. Calculate the length of the vector v, which is 9
  2. Create the vector 1:length(v), which is the vector [1 2 3 4 5 6 7 8 9]
  3. Test whether each element of that vector is less than 10. Since they all are, the result is [1 1 1 1 1 1 1 1 1]
  4. Loop over that vector
So, your for loop is equivalent to
for i = [1 1 1 1 1 1 1 1 1]
prize = prize + v(i);
end
which means you are just summing the 1st element of v, 9 times. That's why you get 18.

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the cyclist
the cyclist am 25 Okt. 2021
Here is one way:
v = [2,3,2,2,1,3,1,10,3];
prize = sum(v(1:find(v==10,1)-1))
prize = 14

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