How to find two arrays of a matrix are equal? and find their location in that matrix??? for example>>> suppose we have a=[1 3 5 6 3 7] how to find which arrays are equal with each other? and find their location??? thank you very much

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vahid torabi 2014-8-18

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评论： Image Analyst 2014-8-18

采纳的回答： Azzi Abdelmalek

example:

a=[1 3 5 6 3 7]; how to find that a(2)=a(5)????

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Answer 1

Azzi Abdelmalek 2014-8-18

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编辑：Azzi Abdelmalek 2014-8-18

在 MATLAB Online 中打开

a=[1 3 5 6 3 7]
[b,ii,jj]=unique(a)
[freq,idx]=histc(a,b)
location=arrayfun(@(x) find(a==x),b,'un',0)
out=[{'a'  'frequency' 'location'};[num2cell([b',freq']) location']]

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vahid torabi 2014-8-18

the order 'unique' makes the matrix form [1 5 2 6 2 7]>>> [1 2 5 6 7] I don't want to change the position of figures!

Image Analyst 2014-8-18

在 MATLAB Online 中打开

vahid, the help has all kinds of information on all the functions. You can consult the help for questions like you just asked, and find answers like this:

[C,ia,ic] = unique(A,setOrder) and [C,ia,ic] = unique(A,'rows',setOrder) return C in a specific order. setOrder='sorted' returns the values (or rows) of C in sorted order. setOrder='stable' returns the values (or rows) of C in the same order as A. If no value is specified, the default is 'sorted'.

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Answer 2

Image Analyst 2014-8-18

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There might be very very many elements that occur more than once in the array. I suggest you call histc() to get a count of all values and see which counts are 2 or greater.

a = randi(9, 1, 100)-5 % Sample data
histEdges = unique(a)
counts = histc(a, histEdges)
% Find locations
for k = 1 : length(counts)
  if counts(k) >= 2
    locations = find(a == histEdges(k))
  end
end