Problem 7. Column Removal

so easy

good problem

GOOD

GOOD

nice

innovative problem

These problems really test our knowledge.

function B = column_removal(A,n)

c=A'
c(n,:)=[]
A=c'
end
Why does my code solve the problem, but it is explicitly an error?

Remember to use () & [] correctly.

super task

Very good. I am new to Matlab. Thanks Mr. Piero Cimule.

Thanks!

great job

B = horzcat(A(1:end,1:n-1), A(1:end,n+1:end)); gives size 35.

How can we know the real leading solution sizes if there are those "message solutions" that are not real solutions?

please delete this solution

woooooooow! good job

I really need to learn to code better. I say this because I keep on getting size which is atleast 2-3 times the size of the leading solution.

larger size but will work for n=1

This would fail for n=1

VERY EASY

good stuff

good

B(n)=A[] ?

What am I doing wrong? Im new btw. Learning the basics.

What is the best optimized solution for this particular problem? Could someone with size 19 or smaller please indicate their solutions. Thanks

My code solves the problem, yet I get incorrect answer

Good one.

no need to use for loop or anything.
it's just this.

nice, I wish I had thought of it this way

nice

can anybody tell me why this solution is not working:"[a,b] = qr(A);
[a1,b1] = qrdelete(a,b,n);
y = a1*b1;"
Although it gives right answers to all test Suits in the software.Plz

because of rounding errors.
B = round(a1*b1);
it should work in this case as all numbers are integers.

B=A(:,1:end-1);

What is wrong here?

you are just removing the "last" column, not the "n-th" column.

I've checked this coding:"[a,b] = qr(A);
[a1,b1] = qrdelete(a,b,n);
B = a1*b1;" Why this not working??? Can anybody check this....

Hi, this code working good. then how to say it is incorrect?

Why the following solution doesn't work? It does on my MATLAB 2011a :

function B = column_removal(A,n)
if((n < 1) || (n > size(A, 2)))
B = A;
return;
end
if(n > 1)
l = A(:, 1:(n-1));
else
l = [];
end
if(n < size(A, 2))
r = A(:, (n+1):size(A, 2));
else
r = [];
end
B = [l,r];
end

Well done!!

Ditto

oops ! didn't read the requirements right

i`m not really sure [] is faster than '' but is good to know

it seems that A(:,n)='' is a bit faster than A(:,n)=[]; but usually we use the latter one,

I can't believe it is this simple. lol.

NICE ONE BUT BIT DIFFICULT

@Óscar yes, you are right. the player can't study the one with well written style

agreed with Oscar

My MATLAB 2012a worked for #2

function ans = column_removal(A,n)

A(:, n) = ''
end

Why doesn't this code work? :/

@Mechatrobrnotronik: I tested your code.
function ans = test_fkt(A,n)
A(:,n) = ''
end
Works for me. Returning A with removed column n.
Nonetheless I am interested in what '' actually does. I couldn't find it in the command reference.

fun

Can the server provide more information on failed solution?

For those who wonder how such low scores are being reported in Cody, it is because many players are changing the actual function call. The result is obvious to those of us who have solved many of these challenges.