MATLAB: This should be easy I have a while loop that is infinite

infinite loopsMATLABwhile loop

When I run this it is inifinite and well that's not what i am looking for… i thought that by limiting the x value to 99 which is in the vector i could get it to stop but that's not the case. any ideas i know that it is going to be something simple…

clc, clear all, close all;

x = 1;

while x <= 99

    x = 1:2:100
end

Best Answer

In MATLAB, conditionals evaluate to true if ALL values of the conditional are non-zero or true. You are repeatedly creating a vector x inside the loop which has all of its values equal to or less than 99, so the conditional will evaluate to true every time. This is why you are getting an infinite loop.

Here is an example, using an IF statement. It evaluates the same way the WHILE loop does:

v = [1 2 -9];  % Notice ALL values are non-zero
if v, disp('IN IF 1'),end
v = [1 0 -9];  % Not all values are non-zero.
if v, disp('IN IF 2'),end

When you do a comparison (>,<,==, etc), you get a logical result. If you do a comparison on an array, you get a logical vector the same size as the array. This will go through a conditional expression the same as v did above: any false (0) values and the expression will not pass the statement.

v>-20  % This will pass [1 1 1]
v<0    % Will not pass, [0 0 1]

What are you trying to achieve with your loop?

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MATLAB: I have a while loop inside a for loop. If the condition of the while loop is not satisfied, I want to jump directly to the end of the for loop. Could anyone please help

Statements a and b are necessary in my code to change the condition 1. Hence I want the entire loop to run such that each iteration of the for loop changes the variables in a way that renders condition1 false. As soon as that happens, I'd like to come out of the for loop.

The goal here is still not entirely clear but based on your comment above, as @Rik Wisselink mentioned, it seems like you want a conditional statement in place of the while loop and a while loop in place of the for loop. Does this do what want it to?

t=0:0.5:100;
lengthT = length(t);
i = 0;
while i <= lengthT          
    if condition1
        disp('Task accomplished')
        statement a
        statement b
        i = i+1;
    else
        break  %When condition1 becomes false, here we enter the while-loop
    end
end
% We end up here if condition1 becomes false -OR- when i>lengthT
statement c

MATLAB: How to save all runs in the while loop

Try this:

allScores = zeros(99,1);
n = 1;
score = 0;
while n < 100
    x = randi(2);
    if (x == 1)
        score = score + 1;
    elseif(x == 2)
        score = score - 1;
    end
    allScores(n) = score;
    n = n + 1;
end
comet(allScores)

Best Answer

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MATLAB: I have a while loop inside a for loop. If the condition of the while loop is not satisfied, I want to jump directly to the end of the for loop. Could anyone please help

MATLAB: How to save all runs in the while loop

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