`continue`

continue 在循环结构用用来跳过本次循环中剩余的代码并在条件求值为真时开始执行下一次循环。

注: 注意在 PHP 中 switch 语句被认为是可以使用 continue 的一种循环结构。

continue 接受一个可选的数字参数来决定跳过几重循环到循环结尾。


<?php
while (list ($key, $value) = each($arr)) {
    if (!($key % 2)) { // skip odd members
        continue;
    }
    do_something_odd($value);
}

$i = 0;
while ($i++ < 5) {
    echo "Outer<br />\n";
    while (1) {
        echo "&nbsp;&nbsp;Middle<br />\n";
        while (1) {
            echo "&nbsp;&nbsp;Inner<br />\n";
            continue 3;
        }
        echo "This never gets output.<br />\n";
    }
    echo "Neither does this.<br />\n";
}
?>

省略 continue 后面的分号会导致混淆。以下例子示意了不应该这样做。


<?php
  for ($i = 0; $i < 5; ++$i) {
      if ($i == 2)
          continue
      print "$i\n";
  }
?>

希望得到的结果是：

可实际的输出是：

因为 print() 调用的返回值是 int(1)，看上去作为了上述可选的数字参数。

add a note User Contributed Notes

szrrya at yahoo dot com
18-Jul-2006 05:18


Documentation states:



"continue is used within looping structures to skip the rest of the current loop iteration"



Current functionality treats switch structures as looping in regards to continue.  It has the same effect as break.



The following code is an example:



<?php

for ($i1 = 0; $i1 < 2; $i1++) {

  // Loop 1.

  for ($i2 = 0; $i2 < 2; $i2++) {

    // Loop 2.

    switch ($i2 % 2) {

      case 0:

        continue;

        break;

    }

    print '[' . $i2 . ']<br>';

  }

  print $i1 . '<br>';

}

?>



This outputs the following:

[0]

[1]

0

[0]

[1]

1



Switch is documented as a block of if...elseif... statements, so you might expect the following output:

[1]

0

[1]

1



This output requires you to either change the switch to an if or use the numerical argument and treat the switch as one loop.

Rene
19-Feb-2006 04:24


(only) the reason that is given on the "Continue with missing semikolon" example is wrong.



the script will output "2" because the missing semikolon causes that the "print"-call is executed only if the "if" statement is true. It has nothing to to with "what" the "print"-call would return or not return, but the returning value can cause to skip to the end of higher level Loops if any call is used that will return a bigger number than 1.



<?php

continue print "$i\n";

?>



because of the optional argument, the script will not run into a "unexpected T_PRINT" error. It will not run into an error, too, if the call after continue does return anything but a number.



i suggest to change it from:

because the return value of the print() call is int(1), and it will look like the optional numeric argument mentioned above.



to

because the print() call will look like the optional numeric argument mentioned above.

net_navard at yahoo dot com
26-Dec-2005 01:01


Hello firends



It is said in manually:

continue also accepts an optional numeric argument which tells it how many levels of enclosing loops it should .



In order to understand better this,An example for that:

<?php



/*continue also accepts an optional numeric argument which 

    tells it how many levels of enclosing loops it should skip.*/



for($k=0;$k<2;$k++)

{//First loop



    

    for($j=0;$j<2;$j++)

    {//Second loop



      for($i=0;$i<4;$i++)

      {//Third loop

    if($i>2)

    continue 2;// If $i >2 ,Then it skips to the Second loop(level 2),And starts the next step,

    echo "$i\n";

       }



    }



}



?>



Merry's christmas :)

    

With regards,Hossein

dedlfix gives me a hint
28-Jan-2005 10:47


a possible solution for 

greg AT laundrymat.tv



I've got the same problem as Greg

and now it works very fine by using

return() instead of continue.



It seems, that you have to use return()

if you have a file included and

you want to continue with the next loop

greg AT laundrymat.tv
15-Jan-2005 12:58


You using continue in a file included in a loop will produce an error.  For example:



//page1.php

for($x=0;$x<10;$x++)

   {

    include('page2.php');    

}



//page2.php



if($x==5)

    continue;

else 

   print $x;



it should print



"012346789" no five, but it produces an error:



Cannot break/continue 1 level in etc.

www.derosetechnologies.com
11-May-2004 11:58


In the same way that one can append a number to the end of a break statement to indicate the "loop" level upon which one wishes to 'break' , one can append a number to the end of a 'continue' statement to acheive the same goal. Here's a quick example:



<?

    for ($i = 0;$i<3;$i++) {

        echo "Start Of I loop\n";

        for ($j=0;;$j++) {

            

            if ($j >= 2) continue 2; // This "continue" applies to the "$i" loop 

            echo "I : $i J : $j"."\n";

        }

        echo "End\n";

    }

?>



The output here is:

Start Of I loop

I : 0 J : 0

I : 0 J : 1

Start Of I loop

I : 1 J : 0

I : 1 J : 1

Start Of I loop

I : 2 J : 0

I : 2 J : 1



For more information, see the php manual's entry for the 'break' statement.

CelloG at phpdoc dot org
02-May-2003 09:55


continue works for:



do

while

switch

for

foreach

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