我是PHP的新手，我正在使用多维数组来处理事件。 由于某种原因，当我使用Foreach函数时，它将为最后一个子数组抛出一个错误。我不确定我做错了什么。
下面是多维数组。密钥按顺序为event_id，day，track和session。
Array
(
[718] => Array
(
[1] => Array
(
[1] => Array
(
[1745] => Array
(
[session_id] => 1745
[event_start_date] => 2010-12-02 09:00
[session_position] => 1
)
[1554] => Array
(
[session_id] => 1554
[event_start_date] => 2010-12-02 09:00
[session_position] => 2
)
[1557] => Array
(
[session_id] => 1557
[event_start_date] => 2010-12-02 09:00
[session_position] => 3
)
[1678] => Array
(
[session_id] => 1678
[event_start_date] => 2010-12-02 09:00
[session_position] => 4
)
)
[2] => Array
(
[1555] => Array
(
[session_id] => 1555
[event_start_date] => 2010-12-02 09:00
[session_position] => 1
)
)
[3] => Array
(
[1649] => Array
(
[session_id] => 1649
[event_start_date] => 2010-12-02 09:00
[session_position] => 1
)
[1672] => Array
(
[session_id] => 1672
[event_start_date] => 2010-12-02 09:00
[session_position] => 2
)
[1651] => Array
(
[session_id] => 1651
[event_start_date] => 2010-12-02 09:00
[session_position] => 3
)
)
)
[2] => Array
(
[2] => Array
(
[1559] => Array
(
[session_id] => 1559
[event_start_date] => 2010-12-02 09:00
[session_position] => 1
)
[1669] => Array
(
[session_id] => 1669
[event_start_date] => 2010-12-02 09:00
[session_position] => 2
)
[1650] => Array
(
[session_id] => 1650
[event_start_date] => 2010-12-02 09:00
[session_position] => 3
)
)
[4] => Array
(
[1652] => Array
(
[session_id] => 1652
[event_start_date] => 2010-12-02 09:00
[session_position] => 1
)
[1561] => Array
(
[session_id] => 1561
[event_start_date] => 2010-12-02 09:00
[session_position] => 2
)
[1654] => Array
(
[session_id] => 1654
[event_start_date] => 2010-12-02 09:00
[session_position] => 3
)
)
[5] => Array
(
[1638] => Array
(
[session_id] => 1638
[event_start_date] => 2010-12-02 09:00
[session_position] => 1
)
[1556] => Array
(
[session_id] => 1556
[event_start_date] => 2010-12-02 09:00
[session_position] => 2
)
[1653] => Array
(
[session_id] => 1653
[event_start_date] => 2010-12-02 09:00
[session_position] => 3
)
)
)
)
）
我正在使用以下代码来显示数组（我将在修复错误后处理它）
reset($rec_info); // the above array
foreach ($rec_info as $rec_event => $event_details) {
echo "event is: " . $rec_event . "<br />";
foreach ($event_details as $rec_day => $day_details){
echo "day is: " . $rec_day . "<br />";
foreach ($day_details as $rec_track => $track_details){
echo "track is: " . $rec_track . "<br />";
foreach ($track_details as $rec_session => $session_details) {
echo "session_id is: " . $session_details["session_id"]. "<br />";
}
}
}
}
显示
event is: 718
day is: 1
track is: 1
session_id is: 1745
session_id is: 1554
session_id is: 1557
session_id is: 1678
track is: 2
session_id is: 1555
track is: 3
session_id is: 1649
session_id is: 1672
session_id is: 1651
day is: 2
Warning: Invalid argument supplied for foreach() in /opt/lampp/htdocs/dev/global.php on line 349
处理其他事件（2-5天之间）时，它始终是抛出此警告的最后一天。
我不明白为什么代码适用于所有其他日子而不是最后一天。就好像数组已超越了界限。我可以使用print_r正确显示所有子数组，除了当天，例如：
echo "<hr> tracks : <pre>"; print_r($track_details); echo "</pre> <br />";
答案 0 :(得分：0)
foreach 仅适用于数组和对象，并会在发出错误时发出错误 您尝试在具有不同数据类型或变量的变量上使用它 未初始化的变量。
在尝试使用foreach()循环非数组之前，您需要检查它们是否是有效数组。
<?php
reset($rec_info); // the above array
if(is_array($rec_info)){
foreach ($rec_info as $rec_event => $event_details) {
echo "event is: " . $rec_event . "<br />";
if(is_array($event_details)){
foreach ($event_details as $rec_day => $day_details){
echo "day is: " . $rec_day . "<br />";
if (is_array($day_details)){
foreach ($day_details as $rec_track => $track_details){
echo "track is: " . $rec_track . "<br />";
if(is_array($track_details)){
foreach ($track_details as $rec_session => $session_details) {
echo "session_id is: " . $session_details["session_id"]. "<br />";
}
}
}
}
}
}
}
}
?>
检查数据库或初始数组是否有任何异常（意外或未关闭的记录）。它可能是行348或349。如果是语法错误，带有PHP标记的正确文本编辑器应突出显示错误。