How to write a program that will randomly return any one of the given statements

Question

Kalyan Dash 2018-3-26

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编辑： Stephen23 2018-3-26

Statement1=He uses Nokia
Statement2=He uses Iphone
Statement3=He uses Samsung
Statement4=He uses Motorola
Statement5=He uses Intex
.
.
.
.
Statement50=He uses Dell

Help me to write a program. The program should return one statement randomly from given fifty statements. And with every run, it must give a different statement.

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Answer 1

Birdman 2018-3-26

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编辑：Birdman 2018-3-26

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Firstly, do not dynamically create variables. There has been a lot of discussion going on about this topic, so you might want to read them.

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Secondly, consider the following approach for your first five statements:

Statement(1)={'He uses Nokia'};
Statement(2)={'He uses Iphone'};
Statement(3)={'He uses Samsung'};
Statement(4)={'He uses Motorola'};
Statement(5)={'He uses Intex'}
randsample(Statement,1)

randsample will return a random statement each time it is run. Hope this helps.

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Stephen23 2018-3-26

编辑：Stephen23 2018-3-26

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Simpler way to define that cell array:

Statement{1} = 'He uses Nokia';
Statement{2} = 'He uses Iphone';
...

or

Statement = {...
    'He uses Nokia',...
    'He uses Iphone',...
    ...
 };

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Answer 2

Jim Riggs 2018-3-26

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编辑：Jim Riggs 2018-3-26

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First, I agree with Birdman, use a single list of values, not N different variables.

I would solve this problem based on creating a "shuffle" routine that will generate a random sequence from 1 to n. Then, on each iteration, simply return the next value in the randomized sequence.

Lout = suffle(N)

Lout is a randomized sequence from 1 to N. The shuffle function works as follows:

First, creat an ordered list from 1 to N

List=linspace(1,N,N)

loop from i=1 to N

on the first pass, select a random number from 1 to N, and copy the sorted to the randomized list;

k = ceil(rand*N)       % k is the random index
Lout(i) = List(k)      % i is the loop index

now remove List(k) from the sorted list (so that it will not be re-used) by copying

for m=k:N-1
   List(m)=List(m+1)
end

now reduce N by 1, and continue. If you started with N=50, N is now 49 and you go back to the start of the loop. When done, you have a randomized sequence of N integers. The whole shuffle function looks like this:

 function Lout = shuffle(N)
 List=linspace(1,N,N);      % create a list from 1 to N
 Lout=zeros(1,N);           % Lout will be the randomized list
 for i=1:N;
     k=ceil(rand*N);   % k is the random index
     Lout(i)=List(k);  % i is the loop index
% now remove the used element from the sorted list
     if k<N
        for m=k:N-1
           List(m) = List(m+1)
        end
     end
     i=i+1;
     N=N-1;
  end