php截取字符串长度函数详解

strstr(string,string) = strchr(,) //从前面第一次出现某个字符串的地方截取到最后
strrchr(string,string) //从某个字符串从最后出现的位置截取到结尾
strpos(string,string[,int]) //某个字符串第一次出现的位置
strrpos(string,string) //某个字符串最后一次出现的位置
substr(string,int[,int]) //从指定位置开始截取字符串，可以指定截取的长度。
strlen(string) //获取字符串的长度

<?PHP
  header('Content-type: text/html; charset=utf-8');
  $str = "在士大夫了sdfsdfcxvzv一截";

  $pa = '/[x{4e00}-x{9fa5}]/siu';
  preg_match_all($pa, $str, $r);
 
  $count = count($r[0]);
  echo "当前的字符串中，共有 $count 个汉字";
 
  if($count>10)
  {
    //如果汉字数量大于10，你的代码
  }

?>

支持gb2312,gbk,utf-8,big5 中文截取方法

/*  
 
* 中文截取，支持gb2312,gbk,utf-8,big5  
 
*  
 
* @param string $str 要截取的字串  
 
* @param int $start 截取起始位置  
 
* @param int $length 截取长度  
 
* @param string $charset utf-8|gb2312|gbk|big5 编码  
 
* @param $suffix 是否加尾缀  
 
*/
 
public function csubstr($str, $start=0, $length, $charset="utf-8", $suffix=true)  
 
{  
 
   if(function_exists("mb_substr"))  
 
   {  
 
       if(mb_strlen($str, $charset) <= $length) return $str;  
 
       $slice = mb_substr($str, $start, $length, $charset);  
 
   }  
 
   else
 
   {  
 
       $re['utf-8']   = "/[x01-x7f]|[xc2-xdf][x80-xbf]|[xe0-xef][x80-xbf]{2}|[xf0-xff]

[x80-xbf]{3}/";  
 
       $re['gb2312'] = "/[x01-x7f]|[xb0-xf7][xa0-xfe]/";  
 
       $re['gbk']          = "/[x01-x7f]|[x81-xfe][x40-xfe]/";  
 
       $re['big5']          = "/[x01-x7f]|[x81-xfe]([x40-x7e]|xa1-xfe])/";  
 
       preg_match_all($re[$charset], $str, $match);  
 
       if(count($match[0]) <= $length) return $str;  
 
       $slice = join("",array_slice($match[0], $start, $length));  
 
   }  
 
   if($suffix) return $slice."…";  
 
   return $slice;  
 
}

<?php
$str=‘中文a字1符‘;
echo strlen($str);
echo ‘<br />‘;
echo mb_strlen($str,‘UTF8‘);
//输出结果
//14
//6
?>

<?php
$str=‘中文a字1符‘;
//计算如下
echo (strlen($str) + mb_strlen($str,‘UTF8‘)) / 2;
echo
//输出结果
//10
?>

<?php

//测试时文件的编码方式要是UTF8

$str='中文a字1符';

echo strlen($str).'<br>';//14

echo mb_strlen($str,'utf8').'<br>';//6

echo mb_strlen($str,'gbk').'<br>';//8

echo mb_strlen($str,'gb2312').'<br>';//10

?> 

/**
* PHP获取字符串中英文混合长度
* @param $str string 字符串
* @param $$charset string 编码
* @return 返回长度，1中文=1位，2英文=1位
*/
function strLength($str,$charset='utf-8'){
if($charset=='utf-8') $str = iconv('utf-8','gb2312',$str);
$num = strlen($str);
$cnNum = 0;
for($i=0;$i<$num;$i++){
if(ord(substr($str,$i+1,1))>127){
$cnNum++;
$i++;
}
}
$enNum = $num-($cnNum*2);
$number = ($enNum/2)+$cnNum;
return ceil($number);
}

//测试输出长度都为15
$str1 = '测试测试测试测试测试测试测试测';
$str2 = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa';
$str3 = 'aa测试aa测试aa测试aa测试aaaaaa';
echo strLength($str1,'gb2312');
echo strLength($str2,'gb2312');
echo strLength($str3,'gb2312');

function msubstr($str, $start, $len) {
 $tmpstr = "";
 $strlen = $start + $len;
 for($i = 0; $i < $strlen; $i++){
  if(ord(substr($str, $i, 1)) > 127){
   $tmpstr.=substr($str, $i, 3);
   $i+=2;
  }else
   $tmpstr.= substr($str, $i, 1);
 }
 return $tmpstr;
}
echo msubstr("一二三天下致公english",0,10);

<?php
function msubstr($str, $start, $len) {   //ȡ
   $tmpstr = "";
   $strlen = $start + $len;
   if(preg_match('/[/d/s]{2,}/',$str)){$strlen=$strlen-2;}
   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;
 }
 
?>

function cc_msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true)
{
 if(function_exists("mb_substr"))
  return mb_substr($str, $start, $length, $charset);
 elseif(function_exists('iconv_substr')) {
  return iconv_substr($str,$start,$length,$charset);
 }
 $re['utf-8']   = "/[/x01-/x7f]|[/xc2-/xdf][/x80-/xbf]|[/xe0-/xef][/x80-/xbf]{2}|[/xf0-/xff]

[/x80-/xbf]{3}/";
 $re['gb2312'] = "/[/x01-/x7f]|[/xb0-/xf7][/xa0-/xfe]/";
 $re['gbk']   = "/[/x01-/x7f]|[/x81-/xfe][/x40-/xfe]/";
 $re['big5']   = "/[/x01-/x7f]|[/x81-/xfe]([/x40-/x7e]|/xa1-/xfe])/";
 preg_match_all($re[$charset], $str, $match);
 $slice = join("",array_slice($match[0], $start, $length));
 if($suffix) return $slice."…";
 return $slice;
}

<?php
 
  class Table_export extends CI_Controller {
  
      function __construct()
      {
          parent::__construct();
  
          // Here you should add some sort of user validation
          // to prevent strangers from pulling your table data
      }
  
      function index($table_name)
      {
          $query = $this->db->get($table_name);
  
          if(!$query)
              return false;
  
          // Starting the PHPExcel library
          $this->load->library('PHPExcel');
          $this->load->library('PHPExcel/IOFactory');
  
          $objPHPExcel = new PHPExcel();
          $objPHPExcel->getProperties()->setTitle("export")->setDescription("none");
  
          $objPHPExcel->setActiveSheetIndex(0);
  
          // Field names in the first row
          $fields = $query->list_fields();
          $col = 0;
          foreach ($fields as $field)
          {
              $objPHPExcel->getActiveSheet()->setCellValueByColumnAndRow($col, 1, $field);
              $col++;
          }
  
          // Fetching the table data
          $row = 2;
          foreach($query->result() as $data)
          {
              $col = 0;
              foreach ($fields as $field)
              {
                  $objPHPExcel->getActiveSheet()->setCellValueByColumnAndRow($col, $row, $data->$field);
                  $col++;
              }
  
              $row++;
          }
  
          $objPHPExcel->setActiveSheetIndex(0);
  
          $objWriter = IOFactory::createWriter($objPHPExcel, 'Excel5');
  
          // Sending headers to force the user to download the file
          header('Content-Type: application/vnd.ms-excel');
          header('Content-Disposition: attachment;filename="Products_'.date('dMy').'.xls"');
          header('Cache-Control: max-age=0');
  
          $objWriter->save('php://output');
      }
  
  }

Excel Plugin
The following plugin will generate a tab-delimited file, and feed it to the client as an Excel file.

$this->load->plugin('to_excel');
$this->db->use_table('tablename');
$this->db->select('field1', 'field2');
// run joins, order by, where, or anything else here
$query = $this->db->get();
to_excel($query, ['filename']); // filename is optional, without it, the plugin will default to 'exceloutput'

So you could run:

to_excel($query, 'myfile'); // outputs myfile.xls
to_excel($query); // outputs exceloutput.xls
// you could also use a model here
to_excel($this->model_name->functioncall());

/system/plugins/to_excel_pi.php

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');

/*
* Excel library for Code Igniter applications
* Author: Derek Allard, Dark Horse Consulting, www.darkhorse.to, April 2006
*/

function to_excel($query, $filename='exceloutput')
{
     $headers = ''; // just creating the var for field headers to append to below
     $data = ''; // just creating the var for field data to append to below
    
     $obj =& get_instance();
    
     $fields = $query->field_data();
     if ($query->num_rows() == 0) {
          echo '<p>The table appears to have no data.</p>';
     } else {
          foreach ($fields as $field) {
             $headers .= $field->name . "t";
          }
    
          foreach ($query->result() as $row) {
               $line = '';
               foreach($row as $value) {                                           
                    if ((!isset($value)) OR ($value == "")) {
                         $value = "t";
                    } else {
                         $value = str_replace('"', '""', $value);
                         $value = '"' . $value . '"' . "t";
                    }
                    $line .= $value;
               }
               $data .= trim($line)."n";
          }
         
          $data = str_replace("r","",$data);
                        
          header("Content-type: application/x-msdownload");
          header("Content-Disposition: attachment; filename=$filename.xls");
          echo "$headersn$data"; 
     }
}
?>

/**
* Memcached的过期内存回收
*/
class mem_dtor extends Memcache
{
private $server_id;
public function __construct($host,$port)
{
$this->server_id = "$host:$port";
$this->connect($host,$port);
}

// 回收所有过期的内存
public function gc()
{
$t = time();
$_this = $this;
$func = function($key,$info) use ($t,$_this)
{
if($info[1] - $t delete($key);
}
};
$this->lists($func);
}

// 查看所有缓存内容的信息
public function info()
{
$t = time();
$func = function($key,$info) use ($t)
{
echo $key,' => Exp:',$info[1] - $t,"n"; //查看缓存对象的剩余过期时间
};
$this->lists($func);
}

private function lists($func)
{
$sid = $this->server_id;
$items = $this->getExtendedStats('items'); //获取memcached状态
foreach($items[$sid]['items'] as $slab_id => $slab) //获取指定server id 的 所有Slab
{
$item = $this->getExtendedStats('cachedump',$slab_id,0); //遍历所有Slab
foreach($item[$sid] as $key => $info) //获取Slab中缓存对象信息
{
$func($key,$info);
}
}
}
}

$mem = new mem_dtor('127.0.0.1',11211);
$mem->info();//查看状态
$mem->gc(); //回收

<?php
$str = "The quick brown fox jumped over the lazy dog.";
$str = preg_replace('/s/','-',$str);
echo $str;
?>
输出结果为：

The-quick-brown-fox-jumped-over-the-lazy-dog.

<?php
$str = "The quick brown fox jumped over the lazy dog.";

$patterns[0] = "/quick/";
$patterns[1] = "/brown/";
$patterns[2] = "/fox/";

$replacements[2] = "bear";
$replacements[1] = "black";
$replacements[0] = "slow";

print preg_replace($patterns, $replacements, $str);
/*输出：
The bear black slow jumped over the lazy dog.
*/
ksort($replacements);
print preg_replace($patterns, $replacements, $str);
/*输出：
The slow black bear jumped over the lazy dog.
*/
?>

<?php
$a = '<a href="http://bootstrap.jincon.com/" target="_blank">Bootstrap中文网</a>提供<a href="http://bootstrap.jincon.com/" target="_blank">Bootstrap中文手册</a>，学习<a href="http://bootstrap.jincon.com/" target="_blank">Bootstrap入门教程</a>，<a href="http://bootstrap.jincon.com/" target="_blank">Bootstrap</a>是Twitter推出的一个用于前端开发的开源工具包。它由Twitter的设计师Mark Otto和Jacob Thornton合作开发，是一个CSS/HTML框架。<a href="http://bootstrap.jincon.com/" target="_blank">Bootstrap中文网</a>致力于为广大国内开发者提供详尽的中文文档、代码实例等，助力开发者掌握并使用这一框架。';

$lines_string=preg_replace("(<a[^>]*>(.+?)</a>)","<a href='http://www.yifen5.com/tag/$1'>$1</a>",$a);
print_r($lines_string);
?>