1 求长度，最基本的

$text = "sunny day";
$count = strlen($text); // $count = 9

2 字符串截取

截取前多少个字符
$article = "BREAKING NEWS: In ultimate irony,man bites dog."; $summary = substr_replace($article,"...",40);

3 算单词数

$article = "BREAKING NEWS: In ultimate irony,man bites dog."; $wordCount = str_word_count($article);
// $wordCount = 8

4 将字符串变成HTML的连接

$url = "W.J. Gilmore,LLC (//www.jb51.cc)";
$url = preg_replace("/http://([A-z0-9./-]+)/","$0",$url);

5 去除字符中的HTML字符串

$text = strip_tags($input,"
"); 6 nl2br:
$comment = nl2br($comment);
变成带HTML格式 7 Wordwrap
限制每行字数
$speech = "Four score and seven years ago our fathers brought forth,upon this continent,a new nation,conceived in Liberty,and dedicated to the proposition that all men are created equal.";
echo wordwrap($speech,30); 输出：
Four score and seven years ago our fathers brought forth,and dedicated to the proposition that all men are created equal.