Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becomes the first. All other columns should be left intact. Return the result in matrix B.
If the input has one column, the output should be identical to the input.
Example:
Input A = [ 12 4 7
5 1 4 ];
Output B is [ 7 4 12
4 1 5 ];
Solution Stats
Problem Comments
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11 Comments
Show
8 older comments
@bmtran (Bryant Tran)
on 27 Jan 2012
need to fix the test suite
Ned Gulley
on 30 Jan 2012
Updated the test so that fliplr will fail. Rescoring. Thanks for all the comments.
Jeevan Thomas
on 9 Apr 2014
Check your test case. Test case with single dimension array is wrong
santosh singh
on 20 Jul 2014
it can be done in many ways
Sukmock
on 1 May 2016
Swapping the first and last columns means the input argument must have columns more than 1.
Thus, the solution, B=1 for A=1, cannot be accepted unless it is clearly written in the problem.
Tanmay Gamit
on 13 Oct 2016
Test 3 B_correct is wrong: where, test B_correct=[3 5 0 2 1] it should be B_correct=[3 2 0 5 1]
Muhlis Ozdemir
on 21 Apr 2017
nice one!
Rukmangadh Sai Myana
on 29 May 2017
nice one!
zefeng chen
on 17 Jun 2017
test 3 is right only 2 columns changed
Pavninder Deol
on 19 Apr 2018
nice
Aliakbar Saifee
on 26 Aug 2018
Why am I getting wrong answer for this [A(:,end),(:,2:end-1),(:,1)]
Solution Comments
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1 Comment
ZUNAED KIBRIA
on 16 Dec 2018
function B = swap_ends(A)
B = A(:,[end , 2:end-1 , 1]);
end
why its not working ??
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1 Comment
Leonardo Farina
on 10 Nov 2018
Se vuoi ti faccio un paio di ripetizioni swap a 5$
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2 Comments
Sudhir Kumar
on 18 Oct 2018
Please Help I have already run this code in matlab but still get wrong here
Sudhir Kumar
on 18 Oct 2018
If Anybody can help me i strongly grateful to him
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1 Comment
go eminem
on 22 Sep 2017
there is problem on this exam
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1 Comment
Aaron Rothlisberger
on 9 Aug 2017
That should work
B = A([end, 2:end-1, 1])
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2 Comments
Aaron Rothlisberger
on 9 Aug 2017
Why isn't this acceptable?
B = A(:,[end, 2:end-1, 1])
Tang
on 12 Aug 2017
When A is a number,end-1=0;it will be wrong;
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2 Comments
kifah alzoubi
on 29 Dec 2016
function [B] = swap_ends(A)
%SWAP_ENDS Solution 19: Swap the first and last columns
if length(A)>1
B=cat(2,A(:,length(A)),A(:,2:length(A)-1),A(:,1));
else
B=A;
end
end
zefeng chen
on 17 Jun 2017
nice
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1 Comment
fahad aljabal
on 29 Dec 2016
.
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1 Comment
Eqin Azlan
on 29 Dec 2016
B=permute(A,4:1) ?
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1 Comment
David Verrelli
on 22 Oct 2016
A couple of comments:
(1) The first case of setting B=1 when there is only one column in A will satisfy the test case on Cody, for which A=[1], but is not a general solution. For example, it would not generate the correct output if A=[7], nor if A=[1; 1].
(2) You have six separate, but identical, evaluations of size(A,2)). It would seem to make sense to evaluate this once only, and to assign it to a variable.
(3) Although your structure of three separate "if" statements clearly works, you could consider using instead "elseif" and "else" within a single "if" statement. Alternatively you could also use "switch, case, otherwise".
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1 Comment
Gary
on 2 Sep 2016
test 3 for correctness is wrong
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1 Comment
JiHong Hu
on 1 Sep 2016
test 3 is error
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1 Comment
John BG
on 25 Jul 2016
please correct the test suite.
Test 3 B_correct is wrong:
where you test B_correct=[3 5 0 2 1]
it should be B_correct=[3 2 0 5 1]
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1 Comment
Atsushi Ueno
on 9 Apr 2016
No, this solution does not cover size(A,2)==2.
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2 Comments
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1 Comment
Przyczajony Tygrys, Ukryty Smok
on 2 Apr 2015
Hmm isn't it a shortest instruction ? :/ any tips ? :)
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1 Comment
Henry Cervantes
on 19 Feb 2015
esta mal evaluado este ejercicio
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2 Comments
SAMET YILDIZ
on 1 Mar 2014
Normally, after writing an A matrix, as I write like A(:,1)=A(:,end); , it is giving the actual result. Where is the mistake ?
Tim
on 3 Mar 2014
You need to change both ends.
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1 Comment
Harald Wie
on 1 Dec 2013
test suite #3 is wrong, i think
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3 Comments
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1 Comment
Isktaine
on 8 Aug 2012
In this function you need only to OVERWRITE the first and last columns, not regenerate the whole thing. for example: A(:,[1 end]) = A(:,[end 1]);
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1 Comment
Abderrahmane
on 27 Jun 2012
the third case also works !!!
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1 Comment
tomio wakasugi
on 5 Apr 2012
My MATLAB worked for Test#3:
>> swap_ends(A)
ans =
3 2 0 5 1
Strange??
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1 Comment
greatordinary
on 3 Mar 2012
This solution works just fine on my matlab..why is cody returning: "Undefined function 'cody.verifyCode' for input arguments of type 'char'."
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2 Comments
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1 Comment
Josh
on 30 Jan 2012
Need to improve test 3. center cols are symmetric, so even though cols 2 and 4 get swapped, the test suite can't validate.
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1 Comment
Mike
on 26 Jan 2012
like the fliplr, this solution is invalid... the test suite is limited.
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2 Comments
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3 Comments
Farhad
on 27 Jan 2012
Incorrect solution. If the array has only one column, this solution generates two columns.
Ned Gulley
on 30 Jan 2012
Actually this solution works just fine. Try it in MATLAB. It doesn't create two columns.
yile
on 22 Feb 2012
You can't just do B = A(:,[end,1])...this would end up two columns if A has only one column. You should do A(:,[1,end]) = A(:,[end,1])) and then B = A
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2 Comments
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1 Comment
Farhad
on 27 Jan 2012
Invalid solution. If the array has one column, this solution generates two columns.
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