Problem 76. De-dupe

Created by MathWorks Cody Team

Solve Later

Remove all the redundant elements in a vector, but keep the first occurrence of each value in its original location. So if

 a = [5 3 6 4 7 7 3 5 9]

then

 dedupe(a) = [5 3 6 4 7 9]

Solve

Solution Stats

6395 Solutions
3801 Solvers

Last Solution submitted on Jan 12, 2026

Last 200 Solutions

Problem Comments

4 Comments

4 Comments

Show 1 older comment

bainhome on 31 Mar 2013

why I use ver.2012b can pass all the tests,but not succeded in cody?
[b,ia]=unique(a,'first');
b=sortrows([b;ia]',2)';
b=b(1,:);

nhagen on 18 Mar 2015

solved in one line !
nice problem

David Verrelli on 7 Feb 2017

Hi, bainhome:
Cody is based on the 'current' version of MATLAB, not R2012b. Many functions are unchanged, but a few have changed (modified, new, or removed), including "unique".
You must add the 'legacy' flag to the list of arguments to preserve the behaviour of the "unique" function from R2012b and prior releases — refer to the documentation (link posted by Jakub Galecki).
—DIV

Hans Kramer on 29 Jun 2018

if u know a specific function its too easy.

Solution Comments

Show comments

Problem Recent Solvers3801

Problem Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Problem 76. De-dupe

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers3801

Suggested Problems

More from this Author96

Problem Tags

Community Treasure Hunt

Problem 76. De-dupe

Solution Stats

Last 200 Solutions

Problem Comments

Solution Comments

Problem Recent Solvers3801

Suggested Problems

More from this Author96

Problem Tags

Community Treasure Hunt

Players