问题描述
您好,我有一个未定义的偏移量0.在此代码内.
Hello i have an Undefined Offset 0 . inside this code.
$q = mysql_query("SELECT * FROM category");
if (false === $q) {
echo mysql_error();
}
while ($r = mysql_fetch_row($q)) {
$names[$r[0]] = $r[2];
$children[$r[0]][] = $r[1];
}
function render_select($root=0, $level=-1) {
global $names, $children;
if ($root != 0)
echo '<option>' . strrep(' ', $level) . $names[$root] . '</option>';
foreach ($children[$root] as $child)
render_select($child, $level+1);
}
echo '<select>';
render_select();
echo '</select>';
错误所在的确切行:
foreach ($children[$root] as $child)
render_select($child, $level+1);
这是用于树形选择框的,我在此问题中找到了此代码
This is for a selectbox with a tree format, i found this code in this question
推荐答案
此处的代码中存在一些歧义:
There is some ambiguity in your code here:
if ($root != 0)
echo '<option>' . strrep(' ', $level) . $names[$root] . '</option>';
foreach ($children[$root] as $child)
render_select($child, $level+1);
如果仅在$root != 0
时尝试执行这三行,则需要添加如下花括号:
If you are attempting to execute these three lines only if $root != 0
, you will need to add curly braces like this:
if ($root != 0)
{
echo '<option>' . strrep(' ', $level) . $names[$root] . '</option>';
foreach ($children[$root] as $child)
{
render_select($child, $level+1);
}
}
否则,任何时候只要不带参数(或第一个参数值为'0')调用render_select
,您都将尝试在数组键'0'处访问$ children的元素.如您的错误所示,$ children在该键处不包含值.
Otherwise, anytime render_select
is called without a parameter (or with a first parameter value of '0') you will attempt to access the element of $children at array key '0'. As your error indicates, $children does not contain a value at that key.
这篇关于未定义的偏移量0,如何设置此数组的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!