本文實例總結(jié)了php常用字符串String函數(shù)。分享給大家供大家參考，具體如下：
nl2br
功能：化換行符為<br>
<?php$str = "cat isn't /n dog";$result = nl2br($str);echo $result;/**結(jié)果cat isn'tdog*/
rtrim
功能：清除右邊的空白
<?php$str = "Hello world ";echo strlen($str)."<br>";$result = rtrim($str);echo strlen($result);/**結(jié)果1411*/
strip_tags
功能：清除字符串中html和php的標記
<?php$str = "<font color = 'red'>Hello world</font>";$result = strip_tags($str);echo $result;/**結(jié)果Hello world*/
strtolower 與 strtoupper
功能：轉(zhuǎn)換成大小寫
<?php$str = "Hello World!";$result = strtolower($str);echo $result."<br>";$result = strtoupper($str);echo $result;/**結(jié)果hello world!HELLO WORLD!*/
trim
功能：去除首尾空格
<?php$str = " Hello World! ";$result = trim($str);echo $str."<br>";echo $result."<br>";echo strlen($str)."<br>";echo strlen($result);/**結(jié)果Hello World!Hello World!1612*/
str_ireplace
功能：替換
<?php$str = "zhang san";$result = str_ireplace("zhang","li",$str);echo $str."<br>";echo $result;/**結(jié)果zhang sanli san*/str_repeat
功能：將一個字符串重復多遍
<?php$str = "Hello jiqing!";$result = str_repeat($str,4);echo $str."<br>";echo $result;/**結(jié)果Hello jiqing!Hello jiqing!Hello jiqing!Hello jiqing!Hello jiqing!*/
str_replace
功能：區(qū)分大小寫的替換
<?php$str = "hello jiqing!";$result1 = str_ireplace("Hello","Hi",$str); //不區(qū)分大小寫$result2 = str_replace("Hello","Hi",$str); //區(qū)分大小寫echo $str."<br>";echo $result1."<br>";echo $result2."<br>";/**結(jié)果hello jiqing!Hi jiqing!hello jiqing!*/str_word_count
功能：返回字符串中單詞的個數(shù)
<?php$str = "hello jiqing a!";$result1 = str_word_count($str); //返回個數(shù)$result2 = str_word_count($str,1); //返回數(shù)組echo $str."<br>";echo $result1."<br>";print_r($result2);/**結(jié)果hello jiqing a!3Array ( [0] => hello [1] => jiqing [2] => a )*/
strlen
功能：返回字符串長度
<?php$str = "hello jiqing a!";$result = strlen($str);echo $result;/**結(jié)果15*/
substr_count
功能：計算一個字符串在另一個字符串中的個數(shù)
<?php$str = "hello jiqing ,hello jim!";$result = substr_count($str,"hello");echo $result;/**結(jié)果2*/
substr_replace
功能：從某個位置開始替換
<?php$str = "hello jiqing ,hello jim!";$result = substr_replace($str,"zhangsan",6);echo $result."<br>";$result = substr_replace($str,"zhangsan",6,6);//從某個位置替換，替換幾個字符串echo $result;/**結(jié)果hello zhangsanhello zhangsan ,hello jim!*/
substr
功能：獲取子字符串
<?php$str = "abcdef";$result = substr($str,0,1); //從第0個開始，獲取1個echo $result."<br>";$result = substr($str,0,-1);//從第0個開始，獲取到除了最后一個的字符串echo $result."<br>";$result = substr($str,2,-1);//從第2個開始，獲取到除了最后一個的字符串echo $result."<br>";$result = substr($str,-3,-1);//從第-3個開始，獲取到除了最后一個的字符串echo $result."<br>";$result = substr($str,-3,1);//從第-3個開始，獲取到除了最后一個的字符串echo $result."<br>";/**結(jié)果aabcdecdeded*/
implode
功能：將數(shù)組轉(zhuǎn)化為字符串
<?php$array = array("2013","6","3");$date = implode("/",$array);echo $date;/**結(jié)果2013/6/3*/md5
功能：對字符串進行md5加密
<?php$str = "Hello world";$result = md5($str);echo $result;/**結(jié)果3e25960a79dbc69b674cd4ec67a72c62*/
希望本文所述對大家PHP程序設計有所幫助。
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