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How to display two non-consecutive column vectors

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MIGUEL HERNANDEZ
MIGUEL HERNANDEZ 2016-9-16
编辑： Jone Cris 2021-9-16
m = [2 3 4; 5 6 7; 8 9 10]
I know how to display 1:3 or 2:3,
b = m(:,1:3)
but I am having difficulties when trying to display just first and third, not to mention when there are more columns.
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Jone Cris
Jone Cris 2021-9-16
编辑：Jone Cris 2021-9-16
Does my answer appropriate with your requirement?
b = m(:,1:2:3)

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采纳的回答

Mischa Kim
Mischa Kim 2016-9-16
Use
b = m(:,[1,3])
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luke hodder
luke hodder 2021-2-2
Thanks for the answer; it would be good if the tutorial by this point had highlighted where to use [ ] over ( ), as it's not been completely clear about it so far. (I tried many solutions including yours but used ( ) instead of [ ])

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更多回答（6 个）

Arvind P
Arvind P 2020-3-28
Try extracting the first, third, and sixth elements of density.
density=[1.4 1.8882 3.090909 4.377 5.090 6.888 7.939 8.98989 9.1225 10.36369]'
%transposed
p=density([1 3 6],:)
p
The answer is
1.4
3.090909
6.888
this is how you extract non consequtive indices in a column
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Steven Agee
Steven Agee 2020-9-20
Thanks for the help, I was getting pretty frustrated with this part.
This would have been nice for the tutorial to explain rather than just tell you to do it.
luke hodder
luke hodder 2021-2-2
Agreed - at this point the course has not actually distinguished between the purposes of ( ) vs [ ], I tried all the combinations of the above but not using square brackets. Very frustrating.

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Khom Raj Thapa Magar
Indices can be non-consecutive numbers. Try extracting the first, third, and sixth elements of density.
Indices can be non-consecutive numbers. Try extracting the first, third, and sixth elements of density.
y = density([1 3 6],:)
KAMOOSH BABA SHAIK
Indices can be non-consecutive numbers. Try extracting the first, third, and sixth elements of density.
p = density([1,3,6])
for non-consecutive numbers
madhanmohan nj
madhanmohan nj 2020-5-26
density=[1.4 1.8882 3.090909 4.377 5.090 6.888 7.939 8.98989 9.1225 10.36369]'
p = density([1,3,6], end)
p = density([1,3,6], :)
basically what is diff between line 2 & 3 ?
  1 个评论
Marianna Nido
Marianna Nido 2020-10-17
I think the diff between line 2 and three is:
-in line 2 you are extracting the 1st, the 3rd and the 6th element of the last column of density
-in line 3, you are extracting the 1st, the 3rd and the 6th element of all columns in density
In this case, the result doesn't change, since density is a vector and not a matrix.
I'm not sure about this, but i think this is the diff.

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ved prakash
ved prakash 2020-10-1
b = density([1,3,6],:)
Kevin Hedrick
Kevin Hedrick 2021-1-5
I used:
y = density(1:2:6)
Then I did a Google search to see how everyone else solved this Further Practice question and it seems I went a whole different route.
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Othmane CHLAIKHY
Othmane CHLAIKHY 2021-2-10
no thats wrong i think your commande will create a vector named Y and containing the first, 3th and the 5th elements and not the 6th
to resolve the probleme, you need to use this type of commande
y = density([1 3 6]);
good luck

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