Home > Article > Backend Development > Summary of some methods for intercepting strings in PHP
Summary of some methods for intercepting strings in PHP
- 不言Original
- 2018-06-21 11:30:222321browse
这篇文章主要介绍了关于PHP截取字符串的一些方法总结，有着一定的参考价值，现在分享给大家，有需要的朋友可以参考一下
现在很多情况下，需要用到截取字符串功能，不够由于gb2312与utf-8的编码问题，需要区别对待，下面是具体的实现方法并从一些比较成熟的系统中扒下的代码。
1、UTF-8、GB2312都支持的汉字截取函数
<?php
/*
Utf-8、gb2312都支持的汉字截取函数
cut_str(字符串, 截取长度, 开始长度, 编码);
编码默认为 utf-8
开始长度默认为 0
*/
function cut_str($string, $sublen, $start = 0, $code = 'UTF-8')
{
if($code == 'UTF-8')
{
$pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/";
preg_match_all($pa, $string, $t_string);
if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."…";
return join('', array_slice($t_string[0], $start, $sublen));
}
else
{
$start = $start*2;
$sublen = $sublen*2;
$strlen = strlen($string);
$tmpstr = '';
for($i=0; $i< $strlen; $i++)
{
if($i>=$start && $i< ($start+$sublen))
{
if(ord(substr($string, $i, 1))>129)
{
$tmpstr.= substr($string, $i, 2);
}
else
{
$tmpstr.= substr($string, $i, 1);
}
}
if(ord(substr($string, $i, 1))>129) $i++;
}
if(strlen($tmpstr)< $strlen ) $tmpstr.= "…";
return $tmpstr;
}
}
$str = "abcd需要截取的字符串";
echo cut_str($str, 8, 0, 'gb2312');
?>2、截取utf8编码的多字节字符串
<?php
//截取utf8字符串
function utf8Substr($str, $from, $len)
{
return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'.
'((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s',
'$1',$str);
}
?>3、截取GB2312中文字符串
<?php
//截取中文字符串
function mysubstr($str, $start, $len) {
$tmpstr = "";
$strlen = $start + $len;
for($i = 0; $i < $strlen; $i++) {
if(ord(substr($str, $i, 1)) > 0xa0) {
$tmpstr .= substr($str, $i, 2);
$i++;
} else
$tmpstr .= substr($str, $i, 1);
}
return $tmpstr;
}
?>4、BugFree 的字符截取函数
<?php
/**
* @package BugFree
* @version $Id: FunctionsMain.inc.php,v 1.32 2005/09/24 11:38:37 wwccss Exp $
*
*
* Return part of a string(Enhance the function substr())
*
* @param string $String the string to cut.
* @param int $Length the length of returned string.
* @param booble $Append whether append "…": false|true
* @return string the cutted string.
*/
function sysSubStr($String,$Length,$Append = false)
{
if (strlen($String) < = $Length )
{
return $String;
}
else
{
$I = 0;
while ($I < $Length)
{
$StringTMP = substr($String,$I,1);
if ( ord($StringTMP) >=224 )
{
$StringTMP = substr($String,$I,3);
$I = $I + 3;
}
elseif( ord($StringTMP) >=192 )
{
$StringTMP = substr($String,$I,2);
$I = $I + 2;
}
else
{
$I = $I + 1;
}
$StringLast[] = $StringTMP;
}
$StringLast = implode("",$StringLast);
if($Append)
{
$StringLast .= "…";
}
return $StringLast;
}
}
$String = "//www.jb51.net — 简单、精彩、通用";
$Length = "18";
$Append = false;
echo sysSubStr($String,$Length,$Append);
?>dedecms中的截取代码
这是从dedecms直接拿的代码，大家可以稍作修改即可。
//中文截取2，单字节截取模式
//如果是request的内容，必须使用这个函数
function cn_substrR($str,$slen,$startdd=0)
{
$str = cn_substr(stripslashes($str),$slen,$startdd);
return addslashes($str);
}
//中文截取2，单字节截取模式
function cn_substr($str,$slen,$startdd=0)
{
global $cfg_soft_lang;
if($cfg_soft_lang=='utf-8')
{
return cn_substr_utf8($str,$slen,$startdd);
}
$restr = '';
$c = '';
$str_len = strlen($str);
if($str_len < $startdd+1)
{
return '';
}
if($str_len < $startdd + $slen || $slen==0)
{
$slen = $str_len - $startdd;
}
$enddd = $startdd + $slen - 1;
for($i=0;$i<$str_len;$i++)
{
if($startdd==0)
{
$restr .= $c;
}
else if($i > $startdd)
{
$restr .= $c;
}
if(ord($str[$i])>0x80)
{
if($str_len>$i+1)
{
$c = $str[$i].$str[$i+1];
}
$i++;
}
else
{
$c = $str[$i];
}
if($i >= $enddd)
{
if(strlen($restr)+strlen($c)>$slen)
{
break;
}
else
{
$restr .= $c;
break;
}
}
}
return $restr;
}
//utf-8中文截取，单字节截取模式
function cn_substr_utf8($str, $length, $start=0)
{
if(strlen($str) < $start+1)
{
return '';
}
preg_match_all("/./su", $str, $ar);
$str = '';
$tstr = '';
//为了兼容mysql4.1以下版本,与数据库varchar一致,这里使用按字节截取
for($i=0; isset($ar[0][$i]); $i++)
{
if(strlen($tstr) < $start)
{
$tstr .= $ar[0][$i];
}
else
{
if(strlen($str) < $length + strlen($ar[0][$i]) )
{
$str .= $ar[0][$i];
}
else
{
break;
}
}
}
return $str;
}phpcms中的字符串截取代码:
function str_cut($string, $length, $dot = '...')
{
$strlen = strlen($string);
if($strlen <= $length) return $string;
$string = str_replace(array(' ', '&', '"', ''', '“', '”', '—', '<', '>', '·', '…'), array(' ', '&', '"', "'", '“', '”', '—', '<', '>', '·', '…'), $string);
$strcut = '';
if(strtolower(CHARSET) == 'utf-8')
{
$n = $tn = $noc = 0;
while($n < $strlen)
{
$t = ord($string[$n]);
if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
$tn = 1; $n++; $noc++;
} elseif(194 <= $t && $t <= 223) {
$tn = 2; $n += 2; $noc += 2;
} elseif(224 <= $t && $t < 239) {
$tn = 3; $n += 3; $noc += 2;
} elseif(240 <= $t && $t <= 247) {
$tn = 4; $n += 4; $noc += 2;
} elseif(248 <= $t && $t <= 251) {
$tn = 5; $n += 5; $noc += 2;
} elseif($t == 252 || $t == 253) {
$tn = 6; $n += 6; $noc += 2;
} else {
$n++;
}
if($noc >= $length) break;
}
if($noc > $length) $n -= $tn;
$strcut = substr($string, 0, $n);
}
else
{
$dotlen = strlen($dot);
$maxi = $length - $dotlen - 1;
for($i = 0; $i < $maxi; $i++)
{
$strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
}
}
$strcut = str_replace(array('&', '"', "'", '<', '>'), array('&', '"', ''', '<', '>'), $strcut);
return $strcut.$dot;
}以上就是本文的全部内容，希望对大家的学习有所帮助，更多相关内容请关注PHP中文网！
相关推荐：
The above is the detailed content of Summary of some methods for intercepting strings in PHP. For more information, please follow other related articles on the PHP Chinese website!
Statement：
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Previous article：Function code for finding polynomial derivatives in PHPNext article：Function code for finding polynomial derivatives in PHP