php中同一个session可以放多个值吗

[nimagetie]

比如
$_session["username"]=""zhangsan1;
$_session["username"]=""zhangsan2;
$_session["username"]=""zhangsan3;
$_session["username"]=""zhangsan4;
$_session["username"]=""zhangsan5;
这样的话是会覆盖 还是全部都在，如何访问其中的某一个，如何全部打印出来?

[Siramizu]

最后一个有效，你可以用数组

<?php
session_start();

$_SESSION['username'] = array();
$_SESSION['username'][] = 'zhangsan1';
$_SESSION['username'][] = 'zhangsan2';
$_SESSION['username'][] = 'zhangsan3';
$_SESSION['username'][] = 'zhangsan4';
$_SESSION['username'][] = 'zhangsan5';

print_r($_SESSION);
?>

另外注意$_SESSION大小写