php常用字符串String函数实例总结【转换,替换,计算,截取,加密】

本文实例总结了php常用字符串String函数。分享给大家供大家参考，具体如下：

nl2br

功能：化换行符为<br>

<?php$str = "cat isn't /n dog";$result = nl2br($str);echo $result;/**结果cat isn'tdog*/

rtrim

功能：清除右边的空白

<?php$str = "Hello world ";echo strlen($str)."<br>";$result = rtrim($str);echo strlen($result);/**结果1411*/

strip_tags

功能：清除字符串中html和php的标记

<?php$str = "<font color = 'red'>Hello world</font>";$result = strip_tags($str);echo $result;/**结果Hello world*/

strtolower 与 strtoupper

功能：转换成大小写

<?php$str = "Hello World!";$result = strtolower($str);echo $result."<br>";$result = strtoupper($str);echo $result;/**结果hello world!HELLO WORLD!*/

trim

功能：去除首尾空格

<?php$str = " Hello World! ";$result = trim($str);echo $str."<br>";echo $result."<br>";echo strlen($str)."<br>";echo strlen($result);/**结果Hello World!Hello World!1612*/

str_ireplace

功能：替换

<?php$str = "zhang san";$result = str_ireplace("zhang","li",$str);echo $str."<br>";echo $result;/**结果zhang sanli san*/

str_repeat

功能：将一个字符串重复多遍

<?php$str = "Hello jiqing!";$result = str_repeat($str,4);echo $str."<br>";echo $result;/**结果Hello jiqing!Hello jiqing!Hello jiqing!Hello jiqing!Hello jiqing!*/

str_replace

功能：区分大小写的替换

<?php$str = "hello jiqing!";$result1 = str_ireplace("Hello","Hi",$str); //不区分大小写$result2 = str_replace("Hello","Hi",$str); //区分大小写echo $str."<br>";echo $result1."<br>";echo $result2."<br>";/**结果hello jiqing!Hi jiqing!hello jiqing!*/

str_word_count

功能：返回字符串中单词的个数

<?php$str = "hello jiqing a!";$result1 = str_word_count($str); //返回个数$result2 = str_word_count($str,1); //返回数组echo $str."<br>";echo $result1."<br>";print_r($result2);/**结果hello jiqing a!3Array ( [0] => hello [1] => jiqing [2] => a )*/

strlen

功能：返回字符串长度

<?php$str = "hello jiqing a!";$result = strlen($str);echo $result;/**结果15*/

substr_count

功能：计算一个字符串在另一个字符串中的个数

<?php$str = "hello jiqing ,hello jim!";$result = substr_count($str,"hello");echo $result;/**结果2*/

substr_replace