php按字符无乱码截取中文的方法

本文实例讲述了php按字符无乱码截取中文的方法。分享给大家供大家参考。具体实现方法如下：

<?php//$str 待截取的字符串//$len 截取的字符个数//$chars 已经截取的字符数//$res  保存的字符串//$chars 保存已经截取的字符串个数//$offset 截取的偏移量//$length 字符串的字节数//若$len>$str的字符个数，造成无谓的while循环，($offset<$length限定)function utf8sub($str,$len){  if($len<=0){    return ;  }  $res="";  $offset=0;  $chars=0;  $length=strlen($str);  while($chars<$len && $offset<$length){    $hign=decbin(ord(substr($str,$offset,1)));      if(strlen($hign)<8){        $count=1;      }elseif(substr($hign,0,3)=="110"){        $count=2;      }elseif(substr($hign,0,4)=="1110"){        $count=3;      }elseif(substr($hign,0,5)=="11110"){        $count=4;      }elseif(substr($hign,0,6)=="111110"){        $count=5;      }elseif(substr($hign,0,7)=="1111110"){        $count=6;      }    $res.=substr($str,$offset,$count);    $offset+=$count;    $chars+=1;  }  return $res;}function utf8sub1($str,$len){  $chars=0;  $res="";  $offset=0;  $length=strlen($str);  while($chars<$len && $offset<$length){    $hign=decbin(ord(substr($str,$offset,1)));    if(strlen($hign)<8){      $count=1;    }elseif($hign & "11100000"=="11000000"){      $count=2;    }elseif($hign & "11110000"=="11100000"){      $count=3;    }elseif($hign & "11111000"=="11110000"){      $count=4;    }elseif($hign & "11111100"=="11111000"){      $count=5;    }elseif($hign & "11111110"=="11111100"){      $count=6;    }    $res.=substr($str,$offset,$count);    $chars++;    $offset+=$count;  }  return $res;}$a="中华ah人民hdj";echo utf8sub($a,5);?>

希望本文所述对大家的php程序设计有所帮助。