MATLAB Functions

Unique elements of a vector

b = unique(a)
b = unique(a,'rows')
[b,index] = unique(...)

Description

b = unique(A)

returns the same values as in A but with no repetitions. The resulting vector is sorted in ascending order. A nonvector input array is regarded as the column vector a = A(:).

b = unique(a,'rows')

returns the unique rows of A.

[b,i,j] = unique(...)

also returns index vectors i and j such that b = a(i) and a = b(j) (or b = a(i,:) and a = b(j,:)).

Examples

a = [1 1 5 6 2 3 3 9 8 6 2 4]
a =
1     1     5     6     2     3     3     9     8     6     2     4
[b,i,j] = unique(a)
b =
      1     2     3     4     5     6     8     9
i =
      2    11     7    12     3    10     9     8
j =
1     1     5     6     2     3     3     8     7     6     2     4
a(i)
ans =
      1     2     3     4     5     6     8     9
b(j)
ans =
1     1     5     6     2     3     3     9     8     6     2     4