while循环中的while循环

Question

我在else语句中有一个while循环。当while循环中的条件为真时，我得到了变量k递减(k=k-1)。我希望在k==0之前停止while循环。我曾尝试将while循环放在另一个while循环(while k>1)中，认为如果k下降到1，可能会取消内部循环。有什么想法吗？

if yada yada
    do thing1
else
    while k>1
        while x==true
            k=k-1;
            do thing2
        end
    end
end

Answer 1

这不是很有效吗？

if yada yada
    x = f(x)   %// If you don't have anything here, you should use "if ~yada yada"
               %// instead of "else"
else
    while k>1 && x == true  %// BTW: Lower case t in true 
        x = g(y)  %// I hope you have something more than "k=k-1" in this loop
        k = k-1;
    end
end

Answer 2

你可以把这句话添加到你最里面的while上

if k <= 1
   break;

Answer 3

由于您的while-loop基本上实现了一个计数器增量，因此我强烈建议您用for-loop替换它(实际上，两者都是)。除了可读性更强之外，它还允许Matlab应用优化，从而大大缩短执行时间。请看这里：

yadayada = false;
x = true;

if yadayada
else
    kmax = 5;          % or whichever maximum value you want k to have
    for k = kmax:-1:2  % have k start at kmax, decrement by 1 each time, until k==2
        fprintf('k = %d\n', k);

        % do something useful in the loop

        if ~x
            break;
        end
    end
end

输出：

k = 5
k = 4
k = 3
k = 2