Mathematical operation on arrays

Dear All, I hope that all are well. I have 4 column vectors, a b c and d. I would like to write a code that take a random value for the first vector a and using that value to delete each value less than it from the vectors b c and d... delete not transfer them to zeros.

I would highly appreciate your help.

[Wan Ji]

You need tell how to delete value in b,c and d by using value from vector a

[Mohammed Lamine Mekhalfia]

The values that are less than the value chosen from the first vector

Answer 1

[the cyclist]

% Set random number seed, for reproducible results in this example
rng default

% Make up the input data
N = 7;
a = rand(N,1);
b = rand(N,1);
c = rand(N,1);
d = rand(N,1);

% Pick random value from a
a_rand = a(randi(numel(a)));
% Delete values from other vectors if they are less than a_rand
b(b<a_rand) = [];
c(c<a_rand) = [];
d(d<a_rand) = [];

% Show the sizes of the resulting vectors
size(a)

ans = 1×2

7 1

size(b)

ans = 1×2

4 1

size(c)

ans = 1×2

5 1

size(d)

ans = 1×2

5 1

[Mohammed Lamine Mekhalfia]

what if I want it to make an index for that value ( I have a column vector so I would like to pick for exemple the 5th value of that vector)?

[the cyclist]

I'm sorry, but I don't understand this question. Specifically,

• I don't know what you are referring to when you say "that value"
• Your original question referencing several vectors, so I am not sure which you mean here

If your original question has been answered, I suggest accepting the answer here, and opening a new question. Try to be as clear and complete as you can, and perhaps give an example. Feel free to tag me (by using @the cyclist) on the new question.

[Mohammed Lamine Mekhalfia]

I meant if instead of a_random ...I would like to refer for a specific value in the vector a ( the value in the 2nd row for example)

[the cyclist]

Instead of

a_rand = a(randi(numel(a)));

use

a(2)

as the value.

This is a very basic MATLAB question. You might want to watch the MATLAB Onramp tutorial to learn the basics.