choose elements from array randomly
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Hi everyone
I have vector array of elements …
for example a=[1,2,3,4]
how can I choose randomly 10% of the above array????
Help me please
majid
采纳的回答
Wayne King
2012-9-23
You must be using an older version of MATLAB, do this instead:
% create vector
a = randn(100,1);
% determine how many elements is ten percent
numelements = round(0.1*length(a));
% get the randomly-selected indices
indices = randperm(length(a));
indices = indices(1:numelements);
% choose the subset of a you want
b = a(indices);
更多回答（2 个）
Azzi Abdelmalek
2012-9-23
编辑：Azzi Abdelmalek
2012-9-23
a=[1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17]
n=length(a)
nr=round(n/10)
out=a(randperm(n,nr))
or if you have'nt randperm
n=length(a);
nr=round(n/10)
[ ~,idx]=sort(rand(n,1));
out=a(idx(1:nr))
1 个评论
Azzi Abdelmalek
2012-9-23
Depends on how you want to round your percentage use, round or ceil or floor
Wayne King
2012-9-23
编辑：Wayne King
2012-9-23
One thing you can do is:
% create vector
a = randn(100,1);
% determine how many elements is ten percent
numelements = round(0.1*length(a));
% get the randomly-selected indices
indices = randperm(length(a),numelements);
% choose the subset of a you want
b = a(indices);
2 个评论
Majid Al-Sirafi
2012-9-23
Wayne King
2012-9-23
See my answer below for a use of randperm compatible with earlier versions of MATLAB
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2012-9-23
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