note 46540 deleted from control-structures.foreach by tomsommer
| From: | tomsommer@php.net | Date: | Thu, 14 Oct 2004 21:13:41 +0000 |
| Subject: | note 46540 deleted from control-structures.foreach by tomsommer | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-78555@lists.php.net to get a copy of this message | ||
Note Submitter: jimmy dot hansen at gmail dot com
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In response to dual iteration using a for instead of foreach (andy at barbigerous dot net,
endofyourself at yahoo dot com):
The while evaluation of your for loop will break only if the last expression in it returns false
when using commas instead of &&/AND*.
<?PHP
// This will continue until list(,$val1) = each($arr1) is false
for( ;
false ,
list(,$val1) = each($arr1)
;
)
// This will break immediately
for( ;
list(,$val1) = each($arr1) ,
false
;
)
// Here is your original example
for(
$someArray1.reset(),
$someArray2.reset();
list(, $someValue1 ) = each( $someArray1 ) ,
list(, $someValue2 ) = each( $someArray2 )
;
)
// This will produce expected results
for(
$someArray1.reset(),
$someArray2.reset();
list(, $someValue1 ) = each( $someArray1 ) &&
list(, $someValue2 ) = each( $someArray2 )
;
)
?>
The one situation where you would want to use a comma is if you wanted to continue iterating until
only your last condition returned false, but this circumstance is rare.
* If using AND, be sure to enclose each condition in parenthesis since && will evaluate
before the assigment operator (=) and AND after.
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Reason: useless note