PHP快速按行读取CSV大文件的封装类分享（也适用于其它超大文本文件）

$csv_file = ‘path/bigfile.csv‘;
$spl_object = new SplFileObject($csv_file, ‘rb‘);
$spl_object->seek(filesize($csv_file));
echo $spl_object->key();

$csv_file = ‘path/bigfile.csv‘;
$start = 100000;  // 从第100000行开始读取
$num = 100;    // 读取100行
$data = array();
$spl_object = new SplFileObject($csv_file, ‘rb‘);
$spl_object->seek($start);
while ($num-- && !$spl_object->eof()) {
 $data[] = $spl_object->fgetcsv();
 $spl_object->next();
}
print_r($data);

class CsvReader {
 private $csv_file;
 private $spl_object = null;
 private $error;

 public function __construct($csv_file = ‘‘) {
  if($csv_file && file_exists($csv_file)) {
   $this->csv_file = $csv_file;
  }
 }

 public function set_csv_file($csv_file) {
  if(!$csv_file || !file_exists($csv_file)) {
   $this->error = ‘File invalid‘;
   return false;
  }
  $this->csv_file = $csv_file;
  $this->spl_object = null;
 }

 public function get_csv_file() {
  return $this->csv_file;
 }

 private function _file_valid($file = ‘‘) {
  $file = $file ? $file : $this->csv_file;
  if(!$file || !file_exists($file)) {
   return false;
  }
  if(!is_readable($file)) {
   return false;
  }
  return true;
 }

 private function _open_file() {
  if(!$this->_file_valid()) {
   $this->error = ‘File invalid‘;
   return false;
  }
  if($this->spl_object == null) {
   $this->spl_object = new SplFileObject($this->csv_file, ‘rb‘);
  }
  return true;
 }
 public function get_data($length = 0, $start = 0) {
  if(!$this->_open_file()) {
   return false;
  }
  $length = $length ? $length : $this->get_lines();
  $start = $start - 1;
  $start = ($start < 0) ? 0 : $start;
  $data = array();
  $this->spl_object->seek($start);
  while ($length-- && !$this->spl_object->eof()) {
   $data[] = $this->spl_object->fgetcsv();
   $this->spl_object->next();
  }
  return $data;
 }

 public function get_lines() {
  if(!$this->_open_file()) {
   return false;
  }
  $this->spl_object->seek(filesize($this->csv_file));
  return $this->spl_object->key();
 }

 public function get_error() {
  return $this->error;
 }
}

include(‘CsvReader.class.php‘);

$csv_file = ‘path/bigfile.csv‘;

$csvreader = new CsvReader($csv_file);

$line_number = $csvreader->get_lines();

$data = $csvreader->get_data(10);

echo $line_number, chr(10);

print_r($data);