foreach多层嵌套的问题,求解~!
<?php
$a1=explode(',','20,21');
$b1=explode(',','20,21');
$c1=explode(',','20,21');
$d1=explode(',','20,21');
$e1=explode(',','20,21');
foreach($a1 as $a ){
foreach($b1 as $b){
foreach($c1 as $c){
foreach($d1 as $d){
foreach($e1 as $e){
}
}
}
}
}
?>
foreach($a1 as $a ){
echo $a;
}
foreach($b1 as $b ){
echo $b;
}