if a=[1,2,3,4] how can i get b=[ (1+2),(1+3),(1+4),(2+3),(2+4),(3+4) ] using for loops,Thanks
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MSP
el 18 de Ag. de 2016
Editada: per isakson
el 1 de En. de 2017
a=[1,2,3,4]
b=[ (1+2),(1+3),(1+4),(2+3),(2+4),(3+4) ]
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Respuesta aceptada
James Tursa
el 18 de Ag. de 2016
Editada: James Tursa
el 18 de Ag. de 2016
The limits on your first for-loop are not correct. In particular, length(a-1) is not the same as length(a)-1. And the limits on your second for-loop are incorrect as well. You need to start the second loop index at i+1, not hard-coded start at 2. Then, for simplicity, maybe just use a counter to update the appropriate index of b. So, make the following changes:
for i=1:length(a-1)
Make the upper limit length(a)-1 instead of length(a-1)
for(k=2:length(a))
Make the lower limit i+1 instead of 2 (and get rid of the outer parentheses)
if(i==k)
b=a(k+1)+a(i)
else
b=a(k)+a(i)
end
No need for an if-test here. Simply set the appropriate element of b to your sum. E.g.,
x = 0; % <-- Do this at the start of your code
:
x = x + 1; % <-- Increment the subscript counter (inside the inner loop)
b(x) = a(k) + a(i); % <-- Set the appropriate element of b to your sum
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Guillaume
el 18 de Ag. de 2016
Here's an answer without a loop. More efficient!
a = 1:4
b = sum(nchoosek(a, 2), 2) %use nchoosek(a, 2) to create [1 2; 1 3; 1 4; 2 3; etc.]
2 comentarios
J. Webster
el 18 de Ag. de 2016
The purpose of homework is to work out things for yourself. Not to go on messageboards and try to get experts to do your work for you.
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