## Unique entries in a vector

| categories: miscellaneous | View Comments

unique_entries

## Unique entries in a vector

John Kitchin

It is surprising how often you need to know only the unique entries in a vector of entries. Matlab provides the unique` to solve these problems. The :command:`unique command returns the sorted unique entries in a vector.

a = [1 1 2 3 4 5 3 5]

unique(a)
a =

1     1     2     3     4     5     3     5

ans =

1     2     3     4     5

The unique command also works with cell arrays of strings.

a = {'a'
'b'
'b'
'c'
'd'
'b'}

unique(a)
a =

'a'
'b'
'b'
'c'
'd'
'b'

ans =

'a'
'b'
'c'
'd'

## There is more!

The unique command has some other features too. check them out:

help unique
UNIQUE Set unique.
B = UNIQUE(A) for the array A returns the same values as in A but
with no repetitions. B will also be sorted. A can be a cell array of
strings.

UNIQUE(A,'rows') for the matrix A 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,:)).

[B,I,J] = UNIQUE(...,'first') returns the vector I to index the
first occurrence of each unique value in A.  UNIQUE(...,'last'),
the default, returns the vector I to index the last occurrence.

cell/unique
dataset/unique
RTW.unique
categorical/unique

Reference page in Help browser
doc unique

'done'

% categories: Miscellaneous
ans =

done