Viewing file:  foreach_as_while.php (2.56 KB) -rw-rw-r--
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<?php
$array = array (1 => "a", 2 => "b", 3 => "c", 4 => "d");
// standard foreach, no references
$temp_array = $array;
while (list ($key, $val) = each ($temp_array))
{
var_export ($key);
var_export ($val);
}
var_export ($array);
reset ($array);
echo "-------------- 1 -----------------\n";
// standard foreach, with references
$temp_array = &$array;
while (list ($key, ) = each (&$temp_array))
{
$val = $temp_array [$key];
var_export ($key);
var_export ($val);
}
var_export ($array);
reset ($array);
echo "-------------- 2 -----------------\n";
// refernce done by in-loop copy, single param to list
while (list ($key) = each (&$temp_array))
{
$val = &$key;
var_export ($key);
var_export ($val);
}
var_export ($array);
reset ($array);
echo "-------------- 3 -----------------\n";
// refernce done by in-loop copy, two params to list
while (list ($key, ) = each (&$temp_array))
{
$val = &$key;
var_export ($key);
var_export ($val);
}
var_export ($array);
reset ($array);
echo "-------------- 4 -----------------\n";
// refernce done by in-loop copy, no list
while ($key = each (&$temp_array))
{
$val = &$key;
var_export ($key);
var_export ($val);
}
var_export ($array);
reset ($array);
echo "-------------- 5 -----------------\n";
// now a foreach
foreach ($array as $key => &$val)
{
$key *= 2;
var_export ($key);
var_export ($val);
}
var_export ($array);
reset ($array);
echo "-------------- 6 -----------------\n";
// with references
// From the php documentation:
// Because assigning an array to another variable resets the original
// arrays pointer, our example above would cause an endless loop had we
// assigned $fruit to another variable inside the loop.
// I can't seem to replicate this
$a = array (6, 5, 6, 23, 7);
reset ($a); // cant reset
while (list ($x, ) = each (&$a))
{
$b = $a;
$c =& $a;
var_export ($a[$x]);
}
echo "\n";
echo "-------------- 7 -----------------\n";
foreach ($a as &$x)
{
$b = $a;
$b[3] = "A"; // php is copy on write
var_export ($b[0]);
var_export ($a);
var_export ($b);
}
echo "-------------- 8 -----------------\n";
foreach ($a as $x)
{
$b = $a;
$b[3] = "A"; // php is copy on write
var_export ($b[0]);
var_export ($a);
var_export ($b);
}
echo "-------------- 9 -----------------\n";
foreach ($a as &$x)
{
// move $a's iterator to the end
while (each ($a)) {}
$b = $a;
$b[3] = "A"; // php is copy on write
var_export ($b[0]);
var_export ($a);
var_export ($b);
}
echo "-------------- 10 ----------------\n";
?>
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