如何从组合数组中获取特定元素？ [重复]

I have two arrays, then i combines them with array_combine() method and now i want to get a secend elemont of new array in thic case: Ben = 37

<?php
$fname=array("Peter","Ben","Joe");
$age=array("35","37","43");
$c=array_combine($fname,$age);
$a = $c[1];
?>

but it outputs erros Notice: Undefined offset: 1 Have i made a mistake? Yep but where?

</div>

After combine you got an associative array, where the second element is not "1" but "Ben" :

<?php
$fname=array("Peter","Ben","Joe");
$age=array("35","37","43");
$c=array_combine($fname,$age);
//$a = $c[1];
$a = $c["Ben"];  // KEY="Ben", VALUE="37".
echo $a;
?>

Edit #1 : get key "Ben" and its value :

<?php
$fname=array("Peter","Ben","Joe");
$age=array("35","37","43");
$c=array_combine($fname,$age);

$keys = array_keys( $c );
echo $keys[ 1 ] .    // "Ben"
     "=" .
     $c[ $keys[1] ]; // "37".
?>

<?php
   $fname=array("Peter","Ben","Joe");
   $age=array("35","37","43");
   $c=array_combine($fname,$age);
   $a = $c['Ben'];

?>

array_combine uses the first parameter as keys and the second as values. so it goes to the result:

Array ( 
    [Peter] => 35 
    [Ben] => 37 
    [Joe] => 43 
)

So you can access the age with the name as key.

$a = $c['Peter']; // 35