how to release indexes in an array

Question

aya qassim 2019-1-16

关闭： MATLAB Answer Bot 2021-8-20

I have the array

arr=[-9,6,-2,0,4,98,2,-5,0,-9,4,3,1,1,-5]

I have wrote this code and found out how many time each element is in the array and the places of the numbers.

how can I make the numbers that appear more than once un the array appear just one time

A=arr;
t=length(A);
A1=repmat(A,t,1);
A2=A';
c=(A1==A2);
r=sum(c);
e=find(r~=1);
disp(e)

Answer 1

madhan ravi 2019-1-16

unique(arr)

aya qassim 2019-1-16

thank you,

but If I want to continue my code, do you know how can I can do it?

Answer 2

Guillaume 2019-1-16

A much simpler way to obtain your r (and e):

[uvals, ~, id] = unique(arr);
r = accumarray(id, 1);
e = find(r > 1);

which also gives you the unique values and answers your how can I make the numbers that appear more than once un the array appear just one time