休息;vs继续；vs回报； [英] break; vs continue; vs return;

问题描述

我从 hotscripts.com

我更新了一些代码以添加新功能，并且看到了一些我不理解的内容.

I updated a little the code to add new functionality and I saw something I don't understand.

在代码中，我看到:

foreach() { ...
 if() ...
  break;
 elseif() ...
  continue;
}

我还看到了:

function() {
// ...
for($nl = 0; ...
 if() ...
  return true;
}

我读到 break; 将停止循环， continue 将跳过循环直至下一次迭代，而 return 将退出该函数.

I read that break; will stop the loop, continue will skip the loop to the next iteration and return will exit the function.

我不明白的是为什么要编码这种样式?为什么不使用类似这样的东西:

What I don't understand is why coding that style? Why not use something like:

function() {
// ...
 for($nl = 0; ...
  if() ...
   $returnValue = true;
  else {
   $returnValue = false;
  }
 }
 return $returnValue;
}

还是for循环中有相同的想法?

or same idea in the for loops?

推荐答案

使用诸如 break 和 continue 之类的关键字可以使代码比您建议的更容易阅读

Using keywords such as break and continue can make the code far easier to read than what you propose.

特别是如果您要嵌套if/else语句超过一个级别.

Especially if you are nesting if/else-statements more than one level.

在这篇文章中比较下面的代码片段，哪一个更容易阅读?他们两个都输出相同的确切内容，而 $ A 是 array(1,2,4,4,3,4).

Compare the snippets further down in this post, which one is easier to read? Both of them output the same exact thing, and $A is array (1,2,4,4,3,4).

在循环中(在函数内部)返回可以节省宝贵的CPU周期，如果您知道不需要进一步循环，为什么这样做?

A return in a loop (inside a function) can save precious CPU cycles, if you know you don't need to loop any further, why do it?

$not_even_found = false;

foreach ($A as $v) {
  if ($v != 1) {
    if ($not_even_found) {
    } else if ($v % 2 != 0) {
      $not_even_found = true;
    } else {
      echo "$v\n";
    }
  }
}

---

我想输入可读的代码.

foreach ($A as $v) {
  if ($v == 1)
    continue;

  if ($v % 2 != 0)
    break;

  echo "$v\n";
}

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