php how to generate dynamic list()?

Question

base on my understanding, this how list() work.

list($A1,$A2,$A3) = array($B1,B2,B3);

So with the help of list() we can assign val

Answer 1

This is not what PHP's list is meant for. From the official PHP docs

list is not really a function, but a language construct. 
list() is used to assign a list of variables in one operation.

In other words, the compiler does not actually invoke a function but directly compiles your code into allocations for variables and assignment.

• You can specifically skip to a given element, by setting commas as follows:

  list($var1, , $var2) = Array($B1, B2, B3);

  echo "$var1 is before $var2 \n";

• or take the third element

  list( , , $var3) = Array($B1, B2, B3);

(I am assuming B2, B3 are constants? Or are you missing a $?)

Specifically using list, you can use PHP's variable variables to create variables from an arbitrary one-dimensional array as follows:

$arr = array("arrindex0" => "apple", "banana", "pear");
reset($arr);
while (list($key, $val) = each($arr)) {
    $key = is_numeric($key) ? "someprefix_" . $key : $key;
    echo "key sdf: $key 
\n";
    $$key = $val;
}
var_dump($arrindex0, $someprefix_0, $someprefix_1);

Result

string 'apple' (length=5)
string 'banana' (length=6)
string 'pear' (length=4)