How can I create a random array like the example C?

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Hang Vu 2019-4-25

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https://ww2.mathworks.cn/matlabcentral/answers/458404-how-can-i-create-a-random-array-like-the-example-c

评论： Hang Vu 2019-4-29

采纳的回答： Stephen23

A=[1 1 2 2 7 7 9 9]

B=[3 5 6 8 10 11] : randomly choose all items from B and input between 2 same number of A

for example : C=[1 8 6 1 2 5 3 2 7 11 7 9 10 9]

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Jan 2019-4-25

Please mention the details: Does the result need to have at least one value of B between the equal elements of A? Does the order of elements of B matter? Does A have an even number of elements in every case so the new elements can be inserted at the indices 2, 4, 6, ...? Providing 1 example does not define the problem completely.

Hang Vu 2019-4-26

Thank you Jan! yes at least one value of B between 2 same number of A, and the B'order is no matter. And A is has 2 same number for each elements so it's even number of elements.

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Stephen23 2019-4-26

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https://ww2.mathworks.cn/matlabcentral/answers/458404-how-can-i-create-a-random-array-like-the-example-c#answer_372383

编辑：Stephen23 2019-4-26

在 MATLAB Online 中打开

A = [1,1,2,2,7,7,9,9];
B = [3,5,6,8,10,11];
Na = numel(A);
Nb = numel(B);
Xb = randperm(Nb) % to shuffle the order of B.
Xa = randperm(Nb-1,Na/2-1);
Xa = diff([0,sort(Xa),Nb]) % the number of elements of B to pick.
T = [num2cell(A(1:2:Na));mat2cell(B(Xb),1,Xa);num2cell(A(2:2:Na))];
C = [T{:}]

Giving (for example):

Xb =
   4   6   3   2   1   5
Xa =
   1   2   2   1
C =
    1    8    1    2   11    6    2    7    5    3    7    9   10    9

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Stephen23 2019-4-26

编辑：Stephen23 2019-4-26

在 MATLAB Online 中打开

"But I quite don't understand the Xa = diff([0,sort(Xa),Nb])."

The concatenation operation [] generates a vector of indices of the ends of blocks of elements, where each block has a random length. The diff then gets those block lengths, which can be used with mat2cell. Because randperm's outputs do not repeat, this guarantees that each block contains at least one element (exactly as you requested).

"I am sorry by misunderstanding but I just realized we can allow 0 element between A"

You wrote that "at least one value of B between 2 same number of A", so that is exactly what my answer does. If you want to change the specification then clearly the code will need to be changed, e.g.:

A = [1,1,2,2,7,7,9,9];
B = [3,5];
Na = numel(A);
Nb = numel(B);
Xb = randperm(Nb) % to shuffle the order of B.
if Nb<=Na/2 % "if don't have enough B to fill in"
	Xa = zeros(1,Na/2);
	Xa(randperm(Na/2,Nb)) = 1; % the number of elements of B to pick.
else
	Xa = randperm(Nb-1,Na/2-1);
	Xa = diff([0,sort(Xa),Nb]) % the number of elements of B to pick.
end
T = [num2cell(A(1:2:Na));mat2cell(B(Xb),1,Xa);num2cell(A(2:2:Na))];
C = [T{:}]

Giving (for example):

Xb =
   1   2
Xa =
   0   1   1   0
C =
   1   1   2   3   2   7   5   7   9   9

Hang Vu 2019-4-26

编辑：Hang Vu 2019-4-29

I just realized I didn't change B to Iminus. Now it works well. Thank you so much!^^

Hang Vu 2019-4-29

在 MATLAB Online 中打开

Could you please help me more on this! for all cases, can be either pick 1 1 or 2 numbers!

Xb =

1 2

Xa =

0 1 1 0 => 0 0 2 0

C =

1 1 2 3 2 7 5 7 9 9 => 1 1 2 2 7 3 5 7 9 9

if Nb<=Na/2 % "if don't have enough B to fill in"
	Xa = zeros(1,Na/2);
	Xa(randperm(Na/2,Nb)) = 1; % the number of elements of B to pick.
else
	Xa = randperm(Nb-1,Na/2-1);
	Xa = diff([0,sort(Xa),Nb]) % the number of elements of B to pick.
end