Detailed explanation of examples of using break to jump out of multiple loops in PHP

break is used in the various loops and switch statements mentioned above. Its function is to jump out of the current grammatical structure and execute the following statements. The break statement can take a parameter n, indicating the number of levels to jump out of the loop. If you want to jump out of multiple loops, you can use n to indicate the number of levels to jump out of. If there is no parameter, the default is to jump out of the current loop.

Code example:

$array = array(1,2,3,4,5,6);
for($i=0;$i<10;$i++){
foreach($array as $key)
{
  echo $key;
  if($key==2){
    break 2;
  }
}
}

Example:

<?php
//设置编码为UTF-8，以避免中文乱码
 header(&#39;Content-Type:text/html;charset=utf-8&#39;);
    //执行嵌套循环，外层循环3次，内层循环2次。当执行到第2次外层循环时，使用break跳出，不执行其内层循环。
    for ($i = 0; $i < 3; $i++){
        echo &#39;外层循环&#39;.$i.&#39; 开始<br/>&#39;;
        for ($j = 0; $j < 2; $j++){
            if ($i == 1){
                break;
            }
            echo &#39;内层循环&#39;.$i.&#39;-&#39;.$j.&#39;<br/>&#39;;
        }
        echo &#39;外层循环&#39;.$i.&#39; 结束<br/><br/>&#39;;
    }
?>

The output page result of the above code is as follows:

Outer loop 0 starts
Inner loop 0-0
Inner loop 0-1
Outer loop 0 end

Outer loop 1 start
Outer loop 1 end

Outer loop 2 start
Inner loop 2-0
Inner loop 2-1
Outer loop 2 End

The above code is easy to understand, break is used to jump out of the current level of loop. However, unlike Java and other programming languages, in PHP, we can also follow the keyword break with a number, which indicates the number of loop levels that need to be jumped out. In this way, a break statement can be used, Jump directly out of multiple loops. For example:

<?php
//设置编码为UTF-8，以避免中文乱码
  header(&#39;Content-Type:text/html;charset=utf-8&#39;);
    //执行嵌套循环，外层循环3次，内层循环2次。当执行到第2次外层循环时，使用break 2跳出，直接跳出2层循环
    for ($i = 0; $i < 3; $i++){
        echo &#39;外层循环&#39;.$i.&#39; 开始<br/>&#39;;
        for ($j = 0; $j < 2; $j++){
            if ($i == 1){
                break 2;    //使用break 2直接跳出2层循环        
            }
            echo &#39;内层循环&#39;.$i.&#39;-&#39;.$j.&#39;<br/>&#39;;
        }
        echo &#39;外层循环&#39;.$i.&#39; 结束<br/><br/>&#39;;
    }
?>

The page results output by the above example code are as follows:

Outer loop 0 starts
Inner loop 0-0
Inner loop 0-1
Outer loop 0 End

Outer loop 1 Start

Therefore, in PHP, we can use break followed by the specified number to directly jump out of the specified number of levels of the loop.
Note: The number followed by break can only be a positive integer and cannot exceed the actual number of loop levels that can be jumped out. Otherwise, a fatal error will be reported.

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