UC知道PHP中while输出问题
来源：百度知道 编辑：UC知道 时间：2024/07/03 00:58:09
<?php
$aa=array(0=>"9016",1=>"9017",2=>"9018");
$i=0;
while($aa)
{
echo $aa[$i];
echo " ";
$i++;
}
?>
为什么出现一系列的错误：
Notice: Undefined offset: 3 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 4 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 5 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 6 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 7 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 8 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 9 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 10 in F:\PHP\PHPnow\htdocs\2.php on line 7
$aa=array(0=>"9016",1=>"9017",2=>"9018");
$i=0;
while($aa)
{
echo $aa[$i];
echo " ";
$i++;
}
?>
为什么出现一系列的错误：
Notice: Undefined offset: 3 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 4 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 5 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 6 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 7 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 8 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 9 in F:\PHP\PHPnow\htdocs\2.php on line 7
Notice: Undefined offset: 10 in F:\PHP\PHPnow\htdocs\2.php on line 7
死循环了,只有条件没有限制。
加个判断 $aa[$i] 不存在就break;
1.死循环
2.数组越界
<?php
$aa=array(0=>"9016",1=>"9017",2=>"9018");
while($aa){
echo array_pop($aa) , '<br>';
}
?>
while($aa)
这个语句有问题了，
改为
while($aa[$i])