Sum of each row ?

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Trevor Badji
Trevor Badji el 10 de Dic. de 2017
Comentada: Image Analyst el 26 de Dic. de 2017
I have [1 1 0; 0 1 0; 0 0 0;] and I want to write that if average of each row > 0.5 it equals 1 , else 0
for the example above, first row 1+1+0 / 3 > 0.5 then it is 1 ..
for i=1:length(nx);
s(i)= sum(nx(i,:))/3;
for n=1:length(nx);
if s(i(n+1))> 0.5;
s(i(n+1)) == 1;
else
s(i(n+1))== 0 ;
end
end
end
  2 comentarios
Star Strider
Star Strider el 10 de Dic. de 2017
What functions are you permitted to use in this obvious homework assignment?
Rena Berman
Rena Berman el 26 de Dic. de 2017
(Answers Dev) Restored edit

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Respuestas (3)

Jos (10584)
Jos (10584) el 10 de Dic. de 2017
Use the matlab way! Use the functions mean, or sum and size. Read the documentation on these functions and pay attention to the dimension argument.
Then take a closer look at logical operators, like >
A = [.9 .7 .4 .6 .2]
B = A > 0.5

Image Analyst
Image Analyst el 10 de Dic. de 2017
Editada: Image Analyst el 10 de Dic. de 2017
Does it have to be a for loop? Why not just do:
rowMeans = mean(nx, 2);
s = zeros(size(nx));
s(rowMeans > 0.5, :) = 1;
You've said both "sum" and "average" - which is it?????. The above is for average. If you want sums, do
rowSums = sum(nx, 2);
s = zeros(size(nx));
s(rowSums > 0.5, :) = 1;
  3 comentarios
Stephen23
Stephen23 el 11 de Dic. de 2017
"There are no specific number of rows therefore i am trying to use for loop to see average of each row"
This makes no sense: vectorized code has no restrictions on how many rows it can handle. Why do you think that a loop is required?
Image Analyst
Image Analyst el 26 de Dic. de 2017
Original question:
I have [1 1 0; 0 1 0; 0 0 0;] and I want to write that if average of each row > 0.5 it equals 1 , else 0
for the example above, first row 1+1+0 / 3 > 0.5 then it is 1 ..
for i=1:length(nx);
s(i)= sum(nx(i,:))/3;
for n=1:length(nx);
if s(i(n+1))> 0.5;
s(i(n+1)) == 1;
else
s(i(n+1))== 0 ;
end
end
end

Iniciar sesión para comentar.


Walter Roberson
Walter Roberson el 10 de Dic. de 2017
mean(nx, 2) > 0.5 %the 2 means "by rows" here.

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