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delete element from vector

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Majid Al-Sirafi
Majid Al-Sirafi ，2012-9-24
评论： Emma Fickett ，2022-10-29
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
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Hamna Ameer
Hamna Ameer 2017-9-29
编辑：Hamna Ameer 2017-9-29
a(3)=[] how can i directly store this in a new vector say b?

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采纳的回答

Daniel Shub
Daniel Shub 2012-9-24
编辑：MathWorks Support Team 2018-11-9
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) = []
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Rik
Rik 2021-3-31
@Anthony Dave Flags are not for personal bookmarks. Please remove your flag.

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更多回答（5 个）

Jan
Jan 2012-9-24
编辑：Jan 2012-9-24
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.
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irvin rynning
irvin rynning 2021-12-6
unfortunately some of us prefer to use Matlab to solve problems in a timely manner, and cannot always engage in stackover-flow style plaudits on criticizing one's peers

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masoud sistaninejad
Ran in:
A = [ 1 2 3 4 5 6 7]
A = 1×7
1 2 3 4 5 6 7
B = [1 3 6]
B = 1×3
1 3 6
C = setdiff(A,B)
C = 1×4
2 4 5 7
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Emma Fickett
Emma Fickett 2022-10-29
I've scoured through so many forums trying to remove a vector of values from another vector and setdiff does exactly what I needed, thank you so much!!

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Andrei Bobrov
Andrei Bobrov 2012-9-24
a = a(abs(a - 3) > eps(100))
Will Reeves
Will Reeves 2022-2-15
really crude, but if you wanted to remove a row defined by and index, rather than a value, you could do something like this:
function out=removeRow(in,index)
% removes a row from an matrix
[~,n]=size(in);
if index>n || index<0
error('index needs to be within the range of the data')
else
if n==1
out=[]; % you've removed the last entry
else
% strip out the required entry
if index==1
out=in(2:end);
elseif index==n
out=in(1:end-1);
else
out=in([1:index-1 index+1:n]);
end
end
end
Elias Gule
Elias Gule 2015-12-1
% Use logical indexing
a = a(a~=3)

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