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用偏移量来访问字符串.

究竟什么是偏移量我也不太懂,不过感觉这种方式象是c语言中字符串的处理方式.

不过说废话,先上代码

<?
$a=”abcde”;
$a[0] = “f”;
echo “$a = $a”;//$a = fbcde
echo “<br>”;
echo “$a[0] = $a[0]“;//$a = f
?>

这里以类似数组的方式来访问了字符串中的字符,但是切记,这和数组完全是两个概念.

再看段代码

<?
$c = null;
$c[0] = “a”;
$c[1] = “b”;
echo “$c is a  $c”;//$c is a Array
echo “<br />”;
echo “$c = “;
print_r($c);
?>

也就是说有了字符串才有这种访问方式,但是用这种方式不能定义字符串.

为了更好的和数组进行区别php还提供了另外一种访问方式,

<?
$b=”abcde”;
$b{1} = “f”;
echo “$b = $b”;//afcde
echo “<br>”;
echo “$b{1} = “.$b{1};
echo “<br>”;
?>

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This entry was posted on Friday, June 8th, 2007 at 3:00 am and is filed under 笔记. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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