delete element from vector
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Majid Al-Sirafi
am 24 Sep. 2012
Kommentiert: Sibghat
am 2 Mär. 2024
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
7 Kommentare
Rosie
am 5 Jul. 2017
Bearbeitet: Walter Roberson
am 5 Jul. 2017
Hi majed
You can use the follwoing
a(index)=[]
a(3)=[]
the number will delete
Good luck
Hamna Ameer
am 29 Sep. 2017
Bearbeitet: Hamna Ameer
am 29 Sep. 2017
a(3)=[] how can i directly store this in a new vector say b?
Akzeptierte Antwort
Daniel Shub
am 24 Sep. 2012
Bearbeitet: MathWorks Support Team
am 9 Nov. 2018
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) = []
6 Kommentare
Weitere Antworten (7)
Jan
am 24 Sep. 2012
Bearbeitet: Jan
am 24 Sep. 2012
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.
3 Kommentare
Joel Bay
am 28 Jun. 2019
"These methods are explained exhaustively in the "Getting Started" chapters of the documentation."
Wrong, definetely not exhaustively after comparing Daniel's answer and the documentation. Logical indexing is not even mentioned. The answers to this question is still useful in 2019.
irvin rynning
am 6 Dez. 2021
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
masoud sistaninejad
am 23 Aug. 2021
A = [ 1 2 3 4 5 6 7]
B = [1 3 6]
C = setdiff(A,B)
2 Kommentare
Emma Fickett
am 29 Okt. 2022
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!!
Will Reeves
am 15 Feb. 2022
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
0 Kommentare
Abdul samad
am 4 Aug. 2023
Bearbeitet: Abdul samad
am 4 Aug. 2023
Yes , you can delete 3 from the given array by assigning the null matrix, like this .
In the command window do like this.
>> a=[1,2,3,4,5];
>> a(3) = [ ];
>>a
This will delete the 3 from the array a = [1,2,3,4,5];
Thank You
0 Kommentare
Sibghat
am 2 Mär. 2024
The removal of the element at the 3rd index has already been addressed. However, if you want to remove all occurences of the number '3' from the array 'a', you can use the following code (with and without using the find method).
% For instance, let's modify the array 'a'
a = [1, 3, 2, 3, 4, 3, 5, 3];
b = find(a == 3); % Find the index of the element to delete
% The above line-of-code will also work without using the find keyword...
a(b) = []; % Delete the element(s)
a
1 Kommentar
Sibghat
am 2 Mär. 2024
And if you want to store the removed values in another variable and display the the exact position of the value. You can do it by either replacing the other values with zeroes or by replacing the desired value with zeroes. Hopefully, the following code will help.
a = [1, 3, 2, 3, 4, 3, 5, 3];
indices_of_3 = find(a == 3); % Find indices of elements equal to 3
removed_values = a(a == 3); % Store the removed values in another variable named 'removed_values'
% Create a vector with zeroes where the number is 3
b = zeros(size(a));
b(a ~= 3) = a(a ~= 3);
% Create a vector with zeroes where the number is not 3
c = zeros(size(a));
c(indices_of_3) = a(indices_of_3);
% Remove all occurrences of 3 from 'original_vector'
a(a == 3) = [];
% Display the results
% Modified vector after removal of all occurrences of 3
a
% Removed values
removed_values
% Displaying zero where values is 3
b
% Displaying zero where value is not 3
c
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