PHP str_replace, 函数的常见用法

<?php
/*Function:
        mixed str_replace ( mixed search, mixed replace, mixed subject [, int &count] )
*/

//1==>
// 输出: <body text='black'>
/*
        这应该是最常见的用法了,从"<body text='%body%'>"中找到"%body%",然后替换成"black"
*/
$bodytag = str_replace("%body%", "black", "<body text='%body%'>");

//2==>
// 输出: Hll Wrld f PHP
/*
        参数 search 为数组的用法,逐个地遍历数组来进行替换
*/
$vowels = array("a", "e", "i", "o", "u", "A", "E", "I", "O", "U");
$onlyconsonants = str_replace($vowels, "", "Hello World of PHP");

//3==>
// 输出: You should eat pizza, beer, and ice cream every day
/*
        参数 search 和 replace 均为数组的用法,且数组元素的个数相同,进行相互对应的替换
*/
$phrase  = "You should eat fruits, vegetables, and fiber every day.";
$healthy = array("fruits", "vegetables", "fiber");
$yummy = array("pizza", "beer", "ice cream");
$newphrase = str_replace($healthy, $yummy, $phrase);

//4==>
// Use of the count parameter is available as of PHP 5.0.0
/*
        输出匹配次数
*/
$str = str_replace("ll", "", "good golly miss molly!", $count);
echo $count; // 2

//5==>
// Order of replacement 
/*
        自定义替换顺序,防止重复替换
*/
$str       = "Line 1\nLine 2\rLine 3\r\nLine 4\n";
$order    = array("\r\n", "\n", "\r");
$replace = '<br />';
// Processes \r\n's first so they aren't converted twice. 
$newstr = str_replace($order, $replace, $str);

//6==>
/*
        这个是需要注意的,参数 search 和 replace 均为数组,第一次先替换 'a' ,结果为 'apple p',第二次接着替换 'p',因此会出现结果 'apearpearle pear'
*/
// Outputs: apearpearle pear
$letters  = array('a', 'p');
$fruit     = array('apple', 'pear');
$text     = 'a p';
$output  = str_replace($letters, $fruit, $text);
echo $output; 
?>