Php 简明教程

PHP - Continue Statement

与 break 语句类似， continue 是 PHP 中的另一个“循环控制语句”。与 break 语句不同， continue 语句会跳过当前迭代，并在条件评估和下一次迭代开始时继续执行。

Like the break statement, continue is another "loop control statement" in PHP. Unlike the break statement, the continue statement skips the current iteration and continues execution at the condition evaluation and then the beginning of the next iteration.

continue 语句可以在任何类型的循环构造中使用，即 for, foreach, while 或 do-while 循环。与 break 类似， continue 关键字通常也以条件方式使用。

The continue statement can be used inside any type of looping constructs, i.e., for, foreach, while or do-while loops. Like break, the continue keyword is also normally used conditionally.

while(expr){
   if (condition){
      continue;
   }
}

以下 flowchart 解释了 continue 语句的工作原理 −

The following flowchart explains how the continue statement works −

php continue statement

Example

以下是一个简单的示例，演示 continue 的用法。预计 for 循环将完成十次迭代。然而，每当计数器 id 为偶数时， continue 语句都会跳过迭代。

Given below is a simple example showing the use of continue. The for loop is expected to complete ten iterations. However, the continue statement skips the iteration whenever the counter id is divisible by 2.

<?php
   for ($x=1; $x<=10; $x++){
      if ($x%2==0){
         continue;
      }
      echo "x = $x \n";
   }
?>

它将生成以下 output −

It will produce the following output −

x = 1
x = 3
x = 5
x = 7
x = 9

Example

continue 语句接受一个可选的数字参数，告诉它应该跳到哪个嵌套循环的末尾。默认值为 1。

The continue statement accepts an optional numeric argument which tells it how many levels of enclosing loops it should skip to the end of. The default is 1.

<?php
   for ($i=1; $i<=3; $i++){
      for ($j=1; $j<=3; $j++){
         for ($k=1; $k<=3; $k++){
            if ($k>1){
               continue 2;
            }
            print "i: $i  j:$j  k: $k\n";
         }
      }
   }
?>

它将生成以下 output −

It will produce the following output −

i: 1  j:1  k: 1
i: 1  j:2  k: 1
i: 1  j:3  k: 1
i: 2  j:1  k: 1
i: 2  j:2  k: 1
i: 2  j:3  k: 1
i: 3  j:1  k: 1
i: 3  j:2  k: 1
i: 3  j:3  k: 1

内嵌 for 循环中的 continue 语句跳过了迭代 2 和 3，并直接跳转到中间循环。因此，输出显示“k”对于“i”和“k”变量的所有值都是 1。

The continue statement in the inner for loop skips the iterations 2 and 3 and directly jumps to the middle loop. Hence, the output shows "k" as 1 for all the values of "i" and "k" variables.