How to assign variables in php with for loop?

assign variables in php with for loop

for($i = 0; $i <= 7; $i++) {
     $name = "variable{$i}";
     $$name = "foo";
}

or

for($i = 0; $i <= 7; $i++) {
     ${"variable$i"} = "foo";
}
or

${"jassi"} .= $_POST['skip'.$daynum];