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:
three
<?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
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.
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>'
;
}
$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
.
' ::: '
.
$v
.
'<br>'
;
}
?>
www.derosetechnologies.com
¶
20 years ago
In the same way that one can append a number to the end of a break statement to indicate the "loop" level upon which one wishes to 'break' , one can append a number to the end of a 'continue' statement to acheive the same goal. Here's a quick example:
<?
for ($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.
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
$i
=
0
;
while (
$i
==
0
) {
$i
++;
echo
"
$i
"
;
if (
$i
==
1
) continue;
}
$i
=
0
;
do {
$i
++;
echo
"
$i
"
;
if (
$i
==
2
) continue;
} while (
$i
==
1
);
?>
Both code snippets would behave exactly the same without continue.
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.
