Problem 25. Remove any row in which a NaN appears

Created by Cody Team

Solve Later

Given the matrix A, return B in which all the rows that have one or more NaNs have been removed. So for

 A = [  1   5   8 
       -3 NaN  14 
        0   6 NaN ];

then

 B = [  1   5   8 ]

Solve

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20873 Solutions
6080 Solvers

Last Solution submitted on Jan 17, 2020

Last 200 Solutions

Problem Comments

18 Comments

18 Comments

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Rednas on 3 Jan 2013

It's a good problem!

gaurav parihar on 17 Oct 2014

very good problem

Shrabya on 1 Nov 2014

ya.. but not so difficult though

Alexander Razmyslov on 30 Jan 2015

nice trick with the " ' "))

Padmanabh Deshmukh on 23 Jun 2015

very good problem

GYStif on 10 Feb 2016

I really like this problem. It makes me to improve my solutions again and again. But it seems that I still use too many loops....

Amninder Dhillon on 19 Aug 2016

lol test case with transform was good one!

SERGII DENEGA on 30 Sep 2016

do not understand how one get so efficient solution on this (and to be honest other problems as well)

JINWOO LEE on 7 Nov 2016

thanks you very much.

Engineer_Josh on 7 Dec 2016

Why doesn't this work? It works when I use it on my computer...
function B = remove_nan_rows(A)
B = A;
B(any(isnan(A')),:) = [];
end

Noriko Hounoki on 24 Dec 2016

MATLABotic!

Cody Colclough on 10 Feb 2017

These types of problems are giving me so many useful functions

Amol Koli on 19 Jul 2017

A(~sum(isnan(A),2),:) this workde for me

André Nóbrega on 9 Aug 2018

Cool!

Arthur Dimitri on 10 Aug 2018

Very good problem!

dymaxwell on 20 Aug 2018

A easy problem if you know fuction isnan.

Divya Yerraguntla on 27 Feb 2019

Nice one!

Le Huu Hai on 18 Sep 2019

Solution Comments

Solution 2055191

1 Comment

1 Comment

Stone Liu on 12 Dec 2019

two NaNs are not equal to each other, using isnan to detect NaNs. Thus,
a = a(all(a==a,2),:);
a = a(~any(isnan(a),2),:);
a(any(a~=a,2),:) = [];
a(any(isnan(a),2),:) = [];

Solution 1257881

1 Comment

1 Comment

Xiaoyi Chin on 19 Sep 2017

really cool!

Solution 1165842

2 Comments

2 Comments

Vishvaksenan A. on 19 Apr 2017

I think that test 4 does not comply to the question.

Amol Koli on 19 Jul 2017

A(~sum(isnan(A),2),:) this worked for me

Solution 1083120

1 Comment

1 Comment

Yoshimasa Nakatani on 16 Dec 2016

O(^-^) o

Solution 1076751

1 Comment

1 Comment

Engineer_Josh on 7 Dec 2016

function B = remove_nan_rows(A)
B = A;
B(any(isnan(A')),:) = [];
end
Why isn't this working?

Solution 931664

1 Comment

1 Comment

YUSUF AKGUNDUZ on 15 Oct 2016

I like the solution

Solution 924942

1 Comment

1 Comment

yao gang on 13 Oct 2016

a = a(all(a==a,2),:); % a = a(~any(isnan(a),2),:);
a(any(a~=a,2),:) = []; % a(any(isnan(a),2),:) = [];
来自知乎

Solution 695994

3 Comments

3 Comments

Ramoflaple on 4 Jul 2015

If I can't view a smaller solution, how can I improve myself ??
I really want to view the better answers.

Matthew Dvorsky on 25 Mar 2016

The only improvement you can really make is making it one line
B = A( not( any(isnan(A), 2 ), :)

zefeng chen on 20 Jun 2017

really?

Solution 693998

2 Comments

2 Comments

Nicholas Hortance on 30 Jun 2015

I really liked this problem. I know that I took a very long approach to it but in time I hope to improve it. I have had a lot of practice with for and while loops which is why I have taken this approach.

ANAND KUMAR on 9 Oct 2015

i am unable to compare it with inf. how can i do that??

Solution 693235

2 Comments

2 Comments

Mark Orloff on 29 Jun 2015

Can anyone tell me why matrix B is not being returned correctly? If I put it one 'end' further into the loop it returns the matrix each time a row is taken out and the tests fail

Ramoflaple on 4 Jul 2015

when you delete one row of B, the size of B changes.
your solution works with an assumption that the size of B won't change.

Solution 533333

1 Comment

1 Comment

Simon on 23 Nov 2014

2 points better than my previous solution with ~any(isnan(

Passes the defined tests, but would fail if Inf was in the test matrices.

Solution 402493

3 Comments

3 Comments

Karthik Raja Arumugam on 12 Feb 2014

Can anyone please tell me how to reduce this size?

Christopher Creutzig on 24 Jul 2014

You already use vectorized assignment. Carry that further and get rid of the for loop.

Brian Butler on 14 Nov 2015

The functions sum() and prod() can reduce row-wise to bring out NaN values. Thus, this express produces logicals for whether each row is in or out...
~isnan(prod(A,2))

Solution 402485

2 Comments

2 Comments

Karthik Raja Arumugam on 12 Feb 2014

Can anyone tell me, how it can coded in size of 10???

Tim on 12 Feb 2014

Using regexp, you can put all the code into a character string, and the character string only has a size of 1.

Solution 341583

1 Comment

1 Comment

Rahul on 29 Oct 2013

Good one...

Solution 4528

3 Comments

3 Comments

Tim on 26 Jan 2012

Would fail if test suite contained any Infs.

David Smith on 31 Jan 2012

^ Yes, this happens to work on the test inputs, but is technically not doing what the problem asks.

Brett Shoelson on 1 May 2012

On the other hand, B = A(all(A==A,2),:) works.

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Problem 25. Remove any row in which a NaN appears

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