find two minimum values not followed by each other.

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FV
FV 2020-4-19
评论： Ameer Hamza 2020-4-20
I am using mink(A,2) to find the two smallest values, but I need to find the two smallest values not followed by each other. How can this be done?
To illustrate: A(1; 1.2; 1.2; 0.7; 0.6; 0.61; 1; 1; 1.2;0.65) I want to find 0.6 and 0.65 and not 0.6 and 0.61.

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采纳的回答

Ameer Hamza
Ameer Hamza 2020-4-19
编辑：Ameer Hamza 2020-4-20
Try this. It also preserve the order of minumum values
A = [0.65;1.2;1.2;0.7;0.6;0.61;1;1;1.2;1];
[vals,idx] = mink(A,3);
if diff(idx(1:2))==1
I = sort(idx([1 3]));
min_vals = A(I);
else
I = sort(idx([1 3]));
min_vals = A(I);
end
Result:
I =
1
5
min_vals =
0.6500
0.6000

更多回答（2 个）

Mehmed Saad
Mehmed Saad 2020-4-19
编辑：Mehmed Saad 2020-4-19
The long Method
A=[1;1.2;1.2;0.7;0.6;0.61;1;1;1.2;0.65];
miny = [];
for i =1:3
x = min(A);
A(A==x) = [];
if(i~=2)
miny = [miny x];
end
end
miny
The short one
A=[1;1.2;1.2;0.7;0.6;0.61;1;1;1.2;0.65];
B = sort(A);
miny = [B(1) B(3)]
  3 个评论
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Image Analyst
Image Analyst 2020-4-19
So the long method is too long, but the short method is too short. Exactly how many lines of code do you want?
FV
FV 2020-4-19
I don't want to sort it and therefore the short one doesn't work. I also need it to work for other A's.

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Image Analyst
Image Analyst 2020-4-19
Try this:
A=[1;1.2;1.2;0.7;0.6;0.61;1;1;1.2;0.65];
% Plot, just for fun.
plot(A, 'r.-', 'MarkerSize', 30);
grid on;
% Find the values in ascending order, so the min value will be at location/index = 1.
[sortedA, sortOrder] = sort(A, 'Ascend')
% Now find the second lowest value but it can't be in the location next to the lowest value.
% Use diff() to see how many indexes the values are separated by each other by.
d = diff(sortOrder) % Don't want 1's
% Get min1 and min2 according to the non-consecutive criteria.
min1 = sortedA(1)
if d(1) ~= 1
% Not consecutive so we're OK.
min2 = sortedA(2) % Get the next one
else
% Consecutive so pick the next location with the next lowest value.
min2 = sortedA(3)
end
If it's homework, don't turn in my work as your own or you could get into trouble with your instructor.
  1 个评论
FV
FV 2020-4-19
This code also just work for this problem. Sometimes it's no smaller values beside the smallest one.
This is not a homework.

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