MATLAB Answers

6

delete element from vector

Asked by Majid Al-Sirafi on 24 Sep 2012
Latest activity Commented on by Joel Bay
on 28 Jun 2019
Hi everyone
how can I delete element from vector .... for example
a=[1,2,3,4,5]
how can I delete 3 from above vector to be
a=[1,2,4,5]
thank you
majid

  7 Comments

Walter Roberson
on 29 Mar 2017
a(3) = [];
Rosie
on 5 Jul 2017
Hi majed
You can use the follwoing
a(index)=[]
a(3)=[]
the number will delete
Good luck
Hamna Ameer on 29 Sep 2017
a(3)=[] how can i directly store this in a new vector say b?

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4 Answers

Daniel Shub
Answer by Daniel Shub
on 24 Sep 2012
Edited by MathWorks Support Team on 9 Nov 2018
 Accepted Answer

I can think of three ways that are all slightly different
a=[1,2,3,4,5];
If you want to get rid of all cases where a is exactly equal to 3
b = a(a~=3);
If you want to delete the third element
b = a;
b(3) = [];
or on a single line
b = a([1:2, 4:end]);
Or, as Jan suggests:
a = [2,3,1,5,4]
a(a == 3) = []

  5 Comments

Walter Roberson
on 16 Jun 2016
Mustafa Uslu comments,
"Practical, fast and accurate!"
how does this work when i need to delete a range of row elements from a vector
Walter Roberson
on 5 Jul 2017
b = a(a >= 2 & a <= 4); %keep 2 to 4

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Jan
Answer by Jan
on 24 Sep 2012
Edited by Jan
on 24 Sep 2012

a = [1,2,3,4,5]
a(3) = []
Or:
a = [2,3,1,5,4]
a(a == 3) = []
These methods are explained exhaustively in the "Getting Started" chapters of the documentation. It is strongly recommended to read them completely. The forum is not though to explain the fundamental basics. Thanks.

  2 Comments

thank you very much
Joel Bay
on 28 Jun 2019
"These methods are explained exhaustively in the "Getting Started" chapters of the documentation."
Wrong, definetely not exhaustively after comparing Daniel's answer and the documentation. Logical indexing is not even mentioned. The answers to this question is still useful in 2019.

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Andrei Bobrov
Answer by Andrei Bobrov
on 24 Sep 2012

a = a(abs(a - 3) > eps(100))

  1 Comment

than you very much

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Answer by Elias Gule
on 1 Dec 2015

% Use logical indexing
a = a(a~=3)

  1 Comment

denny
on 31 Aug 2017
I like this answer.

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