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

example:

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

Answer 1

[Azzi Abdelmalek]

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']]

[vahid torabi]

Thank you very much sir,I really appreciate you.

[vahid torabi]

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]

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'.

Answer 2

[Image Analyst]

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