PHP 会话数组值在第三页丢失

Question

我有一个很长的资料资料sheet我分成了三页
我一直在努力做的是：

start a session on page 1 to carry over array $sda to page 2,

have a session on page 2 to carry over arrays $sda and $sdb data to page 3,

and on page 3, insert all array data to a database and end the session.

但是，在第 3 页上，第 1 页中的数组 $sda 变为空，并且仅传输数组 $sdb。我做错了什么？

这是我的代码：
第 1 页，用户填写表单，值放入数组 $sda，用户点击提交

session_start();
 $_SESSION['sda'] = $sda;
 header("location:enrol.php?a=2");

第 2 页

session_start();
 $sda = $_SESSION['sda'];
 print_r($_SESSION);

用户填写表格，值被放入数组 $sdb，（数组 $sda 中的值应该保留并传递到第 3 页。它实际上不需要打印在这个页面中，但我这样做了检查我是否可以从上一页访问它的内容——工作正常并打印

Array ( [sda] => Array ( [0] => First [1] => Mid [2] => Last [3] => Nick [4] => Cit [5] => Place [6] => January [7] => 1 [8] => 2012 [10] => Grade 1 [9] => School [11] => Home [12] => [13] => A@B.C [14] => [15] => [16] => Guard [17] => Rel [18] => 12345678 [19] => [20] => [21] => [22] => [23] => [24] => [25] => [26] => [27] => [28] => [29] => [30] => [31] => [32] => [33] => [34] => [35] => [37] => [39] => [41] => [36] => [38] => [40] => ) [sdb] => Array ( [9] => [10] => [11] => [12] => [13] => [14] => [15] => [16] => [17] => [18] => [19] => [20] => [21] => a [22] => b [23] => c [24] => d [25] => e [26] => f ) )

用户点击提交（我只想在下一页显示 $sda 值。我做对了吗？:z)

session_start();
 $_SESSION['sda'] = $sda;
 $_SESSION['sdb'] = $sdb;
 header("location:enrol.php?a=3");

第 3 页

session_start();
 $sda = $_SESSION['sda'];
 $sdb = $_SESSION['sdb'];
 print_r($_SESSION);

这里有错误！尽管打印了 $sdb 值，但 $SDA 值丢失了；

Array ( [sda] => [sdb] => Array ( [9] => [10] => [11] => [12] => [13] => [14] => [15] => [16] => [17] => [18] => [19] => [20] => [21] => a [22] => b [23] => c [24] => d [25] => e [26] => f ) )

提交时
保存到数据库并销毁会话

Answer 1

从 return

之后的代码中删除这一行

 user clicks submit (I just want $sda values on the next page. Am I doing it right? :z)

即

  $_SESSION['sda'] = $sda;

PHP 会话数组值在第三页丢失

PHP Session Array Values Lost On Third Page

php

arrays

session