How to make a function that outputs true or false (logical) if a number inputted is in a predetermined vector?

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Jacob Boulrice 2022-3-1

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https://ww2.mathworks.cn/matlabcentral/answers/1661340-how-to-make-a-function-that-outputs-true-or-false-logical-if-a-number-inputted-is-in-a-predetermin

评论： Walter Roberson 2022-3-2

% Here is my code:
function [x] = testLucky1
% testLucky(x) - determine whether x is a lucky number
% return true (1) if x is a lucky number
% return false (0) if x is not a lucky number
secretLucky = [19,22,5,9,11,15,21];
x = input('Enter a number: ');
for k = 1:length(secretLucky)
   if secretLucky(k) == x
       true
   else
       false
   end 
end
% The issue I'm having is that when I enter a single number like
% 19/22/5/9/11/15/21, the command window shows a logical statement of 1
% alongside logical statements of 0.
% For example, if I input 19, the first logical statement in the command
% window will be 1, and the remaining 6 logical statements will be 0.
% My question is, how can I make the output in the command window be a
% SINGLE logical statement of 1 if ANY of the numbers in vector secretLucky 
% is entered? And if a number that is not ANY of the numbers in vector
% secretLucky is entered, how can I have a SINGLE logical statement of 0?
% Does my issue stem from the fact the ouput of true/false is based on my
% variable k? If so what should I do to change this?

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Answer 1

Walter Roberson 2022-3-1

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在 MATLAB Online 中打开

found = false;
for k = 1:10
  if x(k) == 7
    found = true;
  end 
end 
found

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Jacob Boulrice 2022-3-1

Hey, thank you for the response.

Any chance you could explain what this means? And where I should add this in my code?

One question I have is why you set k to 1:10?

Walter Roberson 2022-3-2

The intent is to illustrate initializing a state variable, changing it conditionally, and then examining the state afterwards.

Key point: do not display true when you find a match, set the state variable instead. And do not display the false when a match fails, just go on to the next test. You do not care in this context whether the input did not match 7 out of the 8 possibilities: you only care that it matched one of the possibilities.

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Answer 2

Davide Masiello 2022-3-1

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编辑：Davide Masiello 2022-3-1

在 MATLAB Online 中打开

function testLucky
% testLucky - determine whether x is a lucky number
% return true (1) if x is a lucky number
% return false (0) if x is not a lucky number
secretLucky = [19,22,5,9,11,15,21];
x = input('Enter a number: ');
result = false;
for i = 1:numel(secretLucky)
    if x == secretLucky(i)
        result = true;
    end
end
result
end