Command for picking two regular elements from a Vector

I have a vector of size 30X 1

I want to pick up 1, 2, 4 , 5, 7, 8, 10, 11, ............28, 29.

please suggest me how can i proceed?

[Chaudhary P Patel]

sir, i want all the values except multiple of 3 position.

Answer 1

[Steven Lord]

Use randperm to create shuffled indices then use that index vector to reorder your vector of data. I'll use a deck of cards:

values = ["Ace", 2:10, "Jack", "Queen", "King"];
suits = ["club", "diamond", "heart", "spade"];
cards = combinations(values, suits);
order = randperm(height(cards)); % Random ordering of 1:52
shuffledDeck = cards(order, :); % Use order as indices into rows of cards table

Let's look at the first few cards of the two decks. First the one in order:

head(cards)

    values      suits  
    ______    _________

    "Ace"     "club"   
    "Ace"     "diamond"
    "Ace"     "heart"  
    "Ace"     "spade"  
    "2"       "club"   
    "2"       "diamond"
    "2"       "heart"  
    "2"       "spade"  

Next the shuffled deck.

head(shuffledDeck)

    values      suits  
    ______    _________

    "3"       "club"   
    "8"       "diamond"
    "3"       "heart"  
    "Jack"    "club"   
    "10"      "diamond"
    "7"       "heart"  
    "Ace"     "club"   
    "4"       "club"   

While I used table arrays here (cards, shuffledDeck), the same technique (i.e. shuffledDeck = cards(order, :); ) applies to regular arrays as well.

[Chaudhary P Patel]

How it will be apply for my case?

Answer 2

[Satwik Samayamantry]

Hi Patel, as per my understanding you want to remove all multiples of 3 from your input vector. The following function should get your job done.

function outputVector = removeMultiplesOfThree(inputVector)
    % Initialize an empty output vector
    outputVector = [];
    
    % Iterate through each element in the input vector
    for i = 1:length(inputVector)
        % Check if the current element is not a multiple of 3
        if mod(inputVector(i), 3) ~= 0
            % Append the element to the output vector
            outputVector = [outputVector; inputVector(i)];
        end
    end
end

Hope this helps you!!

[Matt J]

yourVector=randi(100,1,30) %Example

yourVector = 1×30

37 5 81 91 82 46 93 29 17 47 9 83 86 37 85 59 84 33 12 71 79 90 88 30 83 33 68 80 45 70

N=numel(yourVector);

subset=setdiff(1:N,3:3:N);

yourVector=yourVector(subset)  %Result

yourVector = 1×20

37 5 91 82 93 29 47 9 86 37 59 84 12 71 90 88 83 33 80 45