這篇文章主要介紹php常用字串函數,有興趣的朋友參考下,希望對大家有幫助。
閱讀目錄
確定字串長度
比較字串
#分割連接反轉
html與字串相互轉換
#填充與剔除字串
#統計字元與單字數
找出取代截取
大小寫處理
#php內建了98個字串函數(除了基於正規表示式的函數,正規表示式在此不在討論範圍),能夠處理字串中能遇到的每一個面向內容,本文對常用字串函數進行簡單的小結,主要包含以下8部分:1.確定字串長度、2.比較字串、3.分割連接反轉、4.html與字串相互轉換、5.填充和剔除字串、6.統計字元和單字數、7.找出替換截取、8.大小寫處理。
strlen函數和mb_strlen函數,後者需要開啟mbstring擴充
<?php header('content-type:text/html;charset=utf-8'); $str = 'abcdef'; echo strlen($str); // 6 echo "<br/>"; $str = ' ab cd '; echo mb_strlen($str); // 7 echo "<br/>"; //strlen 是计算字符串"字节"长度 //mb_strlen,是根据编码,计算字符串的"字符"个数. $str='中华人民共和国'; echo "字节长度是".strlen($str);//在 UTF-8编码下,一个汉字占3个字节 在gbk中一个汉字占2个字节 echo "<br/>"; echo "字符长度是".mb_strlen($str,'utf-8'); ?>
strcmp函數、strcasecmp函數、strspn函數、strcspn函數
<?php $pwd="userpwd"; $pwd2="Userpwd"; //区分大小写 if (strcmp($pwd, $pwd2) !=0) { echo "password do not match"; } else{ echo "password match"; } $email1="www.baidu.com"; $email2="WWW.BAIDU.COM"; //不区分大小写 if (!strcasecmp($email1, $email2)) { echo "ok",'<br>'; } //求两个字符串相同的部分 $password="1233345"; if (strspn($password,"1234567890")==strlen($password)) { echo "the password connot consist solely of numbers"; } // $password="a12345"; if (strcspn($password, "1234567890")==0) { echo "the password connot consist solely of numbers"; } ?>
#str_split函數、split函數、explode函數和implode函數
<?php header('content-type:text/html;charset=utf-8'); $str = "Hello Friend"; $arr1 = str_split($str); print_r($arr1); $arr2 = str_split($str, 3); print_r($arr2); $str = 'abc,中国,美国,日本'; // explode,是根据指定的分割符,把字符串拆成数组. $arr = explode(',',$str); print_r($arr); // implode,是根据指定的连接符,把数组再拼接成字符串 $arr = explode(',',$str); echo implode('~',$arr),'<br />'; // 你可以只传一个数组做参数,不指定连接符, // 这样,将把数组单元直接拼接起来 echo implode($arr); ?>
htmlspecialchars函數、strip_tags函數、get_html_translation_table函數和addcslashes函數和htmlentities函數
<?php $str = "hello ', world"; echo $str,'<br />'; echo $str= addslashes($str),'<br />'; echo stripslashes($str),'<br />'; $str = '<ab>'; echo $str,'<br />'; echo htmlspecialchars($str); echo "</br>"; $str="Email <a href='admin@qq.com'>example@qq.com</a>"; echo strip_tags($str); ?>
trim函式、ltrim函式、rtrim函式、str_pad函式、chunk_split函式
<?php $str = '12345678'; echo chunk_split($str,3,','); echo "<br>"; $text = "\t\tThese are a few words :) ... "; echo trim($text); echo "<br>"; echo ltrim($text,'\t'),'<br>'; echo rtrim($text,'\r'),'<br>'; echo str_pad('apple', 6)."is good."; ?>
count_chars函數和str_word_count
<?php $data = "Two Ts and one F."; foreach (count_chars($data, 1) as $i => $val) { echo "There were $val instance(s) of \"" , chr($i) , "\" in the string.\n"; } echo "<hr>"; $str = "Hello fri3nd, you're looking good today!"; print_r(str_word_count($str, 1)); ?>
<?php $substr = "index.html"; $log = <<< logfile 192.168.1.11:/www/htdocs/index.html:[2016/08/10:21:58:27] 192.168.1.11:/www/htdocs/index.html:[2016/08/18:01:51:37] 192.168.1.11:/www/htdocs/index.html:[2016/08/20:11:48:27] logfile; $pos =strpos($log, $substr); $pos2=strpos($log,"\n",$pos); $pos=$pos+strlen($substr)+1; $timestamp=substr($log,$pos,$pos2-$pos); echo "The file $substr was first accessed on:$timestamp"; echo "<br>"; $author="lester@example.com"; $author=str_replace("@", "at", $author); echo "connect the author of this article at $author"; echo "<br>"; echo ltrim(strstr($author,"@"), "@"); ?>
回到目录
<?php $url="http://WWWW.BAIDU.COM"; echo strtolower($url),'<br>'; $str="hello world"; echo strtoupper($str),'<br>'; $str="php is the most popular language "; echo ucfirst($str),'<br>'; echo ucwords($str); ?>
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