# 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 on 1 Mar 2022
Commented: Walter Roberson on 2 Mar 2022
% 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?

Walter Roberson on 1 Mar 2022
found = false;
for k = 1:10
if x(k) == 7
found = true;
end
end
found
Jacob Boulrice on 1 Mar 2022
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 on 2 Mar 2022
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.

Davide Masiello on 1 Mar 2022
Edited: Davide Masiello on 1 Mar 2022
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
Jacob Boulrice on 1 Mar 2022
Unfortentatly I need to use a for loop. We just learned about them in class so this homework is meant to teach me how to use them.
Davide Masiello on 1 Mar 2022

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