1.str_replace();
$a='12345';
$b='23456677';
$a .= $b;
$b = str_replace($b,'',$a);
$a = str_replace($b,'',$a);
echo '$a'.$a.'$b'.$b;
2.list()
$a = 'aaa';
$b = 'bbb';
list($b,$a) = array($a,$b);
1.str_replace();
$a='12345';
$b='23456677';
$a .= $b;
$b = str_replace($b,'',$a);
$a = str_replace($b,'',$a);
echo '$a'.$a.'$b'.$b;
2.list()
$a = 'aaa';
$b = 'bbb';
list($b,$a) = array($a,$b);