PHP Velho Oeste 2024

continue

(PHP 4, PHP 5, PHP 7, PHP 8)

continue is used within looping structures to skip the rest of the current loop iteration and continue execution at the condition evaluation and then the beginning of the next iteration.

Note: In PHP the switch statement is considered a looping structure for the purposes of continue. continue behaves like break (when no arguments are passed) but will raise a warning as this is likely to be a mistake. If a switch is inside a loop, continue 2 will continue with the next iteration of the outer loop.

continue accepts an optional numeric argument which tells it how many levels of enclosing loops it should skip to the end of. The default value is 1, thus skipping to the end of the current loop.

<?php
$arr
= ['zero', 'one', 'two', 'three', 'four', 'five', 'six'];
foreach (
$arr as $key => $value) {
if (
0 === ($key % 2)) { // skip members with even key
continue;
}
echo
$value . "\n";
}
?>

The above examples will output:

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

The above examples will output:

Outer
Middle
Inner
Outer
Middle
Inner
Outer
Middle
Inner
Outer
Middle
Inner
Outer
Middle
Inner

Omitting the semicolon after continue can lead to confusion. Here's an example of what you shouldn't do.

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

One can expect the result to be:

0
1
3
4

Changelog for continue
Version Description
7.3.0 continue within a switch that is attempting to act like a break statement for the switch will trigger an E_WARNING.

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User Contributed Notes 7 notes

up
138
jaimthorn at yahoo dot com
14 years ago
The remark "in PHP the switch statement is considered a looping structure for the purposes of continue" near the top of this page threw me off, so I experimented a little using the following code to figure out what the exact semantics of continue inside a switch is:

<?php

   
for( $i = 0; $i < 3; ++ $i )
    {
        echo
' [', $i, '] ';
        switch(
$i )
        {
            case
0: echo 'zero'; break;
            case
1: echo 'one' ; XXXX;
            case
2: echo 'two' ; break;
        }
        echo
' <' , $i, '> ';
    }

?>

For XXXX I filled in

- continue 1
- continue 2
- break 1
- break 2

and observed the different results.  This made me come up with the following one-liner that describes the difference between break and continue:

continue resumes execution just before the closing curly bracket ( } ), and break resumes execution just after the closing curly bracket.

Corollary: since a switch is not (really) a looping structure, resuming execution just before a switch's closing curly bracket has the same effect as using a break statement.  In the case of (for, while, do-while) loops, resuming execution just prior their closing curly brackets means that a new iteration is started --which is of course very unlike the behavior of a break statement.

In the one-liner above I ignored the existence of parameters to break/continue, but the one-liner is also valid when parameters are supplied.
up
43
Nikolay Ermolenko
15 years ago
Using continue and break:

<?php
$stack
= array('first', 'second', 'third', 'fourth', 'fifth');

foreach(
$stack AS $v){
    if(
$v == 'second')continue;
    if(
$v == 'fourth')break;
    echo
$v.'<br>';
}
/*

first
third

*/

$stack2 = array('one'=>'first', 'two'=>'second', 'three'=>'third', 'four'=>'fourth', 'five'=>'fifth');
foreach(
$stack2 AS $k=>$v){
    if(
$v == 'second')continue;
    if(
$k == 'three')continue;
    if(
$v == 'fifth')break;
    echo
$k.' ::: '.$v.'<br>';
}
/*

one ::: first
four ::: fourth

*/

?>
up
21
Koen
11 years ago
If you use a incrementing value in your loop, be sure to increment it before calling continue; or you might get an infinite loop.
up
18
rjsteinert.com
13 years ago
The most basic example that print "13", skipping over 2.

<?php
$arr
= array(1, 2, 3);
foreach(
$arr as $number) {
  if(
$number == 2) {
    continue;
  }
  print
$number;
}
?>
up
11
www.derosetechnologies.com
19 years ago
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.
up
2
tufan dot oezduman at gmail dot com
17 years ago
a possible explanation for the behavior of continue in included scripts mentioned by greg and dedlfix above may be the following line of the "return" documentation: "If the current script file was include()ed or require()ed, then control is passed back to the calling file."
The example of greg produces an error since page2.php does not contain any loop-operations.

So the only way to give the control back to the loop-operation  in page1.php would be a return.
up
0
Geekman
16 years ago
For clarification, here are some examples of continue used in a while/do-while loop, showing that it has no effect on the conditional evaluation element.

<?php
// Outputs "1 ".
$i = 0;
while (
$i == 0) {
   
$i++;
    echo
"$i ";
    if (
$i == 1) continue;
}

// Outputs "1 2 ".
$i = 0;
do {
   
$i++;
    echo
"$i ";
    if (
$i == 2) continue;
} while (
$i == 1);
?>

Both code snippets would behave exactly the same without continue.
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