The best way to read large files in php_PHP tutorial

The best way to read large files in php

We usually read large files in php line by line instead of writing the file all at once into the memory. Yes, this will cause the php program to freeze. Here is an example for you.

The code is as follows

Read the last few lines of data from a large file: /** * Get the last $n lines of the file * @param string $filename file path * @param int $n the last few lines * @return mixed false indicates an error, and if successful, returns a string ​*/ function FileLastLines($filename,$n){ If(!$fp=fopen($filename,’r')){ echo "Failed to open the file, please check whether the file path is correct. The path and file name do not contain Chinese characters";          return false; } $pos=-2; $eof=””; $str=””; While($n>0){ ​​​​while($eof!=”n”){ If(!fseek($fp,$pos,SEEK_END)){                      $eof=fgetc($fp);                   $pos–;           }else{                   break;             } }            $str.=fgets($fp);          $eof=””;          $n–; } Return $str; } echo nl2br(FileLastLines(‘sss.txt’,4)); /*** Get the last $n lines of the file * @param string $filename file path * @param int $n The last few lines * @return mixed false means there is an error, and return a string if successful*/ function FileLastLines($filename,$n){ if(!$fp=fopen($filename,'r')){ echo "Failed to open the file, please check whether the file path is correct, the path and The file name should not contain Chinese characters "; " !fseek($fp,$pos,SEEK_END)){                                                                                        $str.=fgets($fp); $n--; } } return $str; } echo nl2br(FileLastLines('sss.txt',4)); function tail($fp,$n,$base=5) { assert($n>0); $pos = $n+1; $lines = array(); while(count($lines)< =$n){ try{ fseek($fp,-$pos,SEEK_END); } catch (Exception $e){ fseek(0); break; } $pos *= $base; while(!feof($fp)){ array_unshift($lines,fgets($fp)); } } return array_slice($lines,0,$n); } var_dump(tail(fopen("access.log","r+"),10)); $fp = fopen($file, "r"); $line = 10; $pos = -2; $t = " "; $data = ""; while ($line > 0) { while ($t != "n") { fseek($fp, $pos, SEEK_END); $t = fgetc($fp); $pos --; } $t = " "; $data .= fgets($fp); $line --; } fclose ($fp); echo $data

http://www.bkjia.com/PHPjc/850928.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/850928.htmlTechArticleThe best way to implement php to read large files. We usually talk about the method of reading large files in php line by line. Instead of writing all the files into the memory at once, this will cause the php program to freeze...