注意：未定义的索引：第164行的C：\\ wamp \\ www \\ blog \\ news.php中的pre

Question

I am making a blog for myself in Dreamweaver and well I have run into some trouble, I want to display text from a database and yet it won't work for some reason. I keep getting this error:

Notice: Undefined index: pre in C:\\wamp\\www\\blog\\news.php on line 164 This is the block of code where the error is:

  <div id="blog_posts">
<?php do { ?>
  <h2><?php echo $row_getDisplay['title']; ?></h2>
  <p class="updated"><?php echo $row_getDisplay['formatted']; ?></p>
  <p><?php echo $row_getDisplay['pre']; ?></p>
  <?php } while ($row_getDisplay = mysql_fetch_assoc($getDisplay)); ?>

Can anyone please help? I have been trying for days!

Answer 1

使用while(...) { }循环而不是do { } while(...)循环，这样$row_getDisplay会在第一次迭代时初始化。

Answer 2

In your array there are not index 'pre'...

You can use

echo isset($row_getDisplay['pre'])?$row_getDisplay['pre']:'';

for using your code with incorrect index.

Answer 3

PHP indicating the problem is that there index "pre". Try to make an inspection of the variable $ row_getDisplay using var_dump() (http://www.php.net/manual/en/function.var-dump.php). With this function you can check if the "pre" exists in the array of fields.

<div id="blog_posts">
<?php do { ?>
<?php var_dump($row_getDisplay); ?>
  <h2><?php echo $row_getDisplay['title']; ?></h2>
  <p class="updated"><?php echo $row_getDisplay['formatted']; ?></p>
  <p><?php echo $row_getDisplay['pre']; ?></p>
  <?php } while ($row_getDisplay = mysql_fetch_assoc($getDisplay)); ?>

Regards!.

Answer 4

只需检查数组的内容，然后回显"<pre>",print_r($row_getDisplay, TRUE),"</pre>"以便可以查看其内容，里面可能没有pre index pre