SplFileObject::next

(PHP 5 >= 5.1.0, PHP 7, PHP 8)

SplFileObject::next — Read next line

说明

public SplFileObject::next ( ) : void

Moves ahead to the next line in the file.

参数

此函数没有参数。

返回值

没有返回值。

范例

Example #1 SplFileObject::next() example


<?php
// Read through file line by line
$file = new SplFileObject("misc.txt");
while (!$file->eof()) {
    echo $file->current();
    $file->next();
}
?>

参见

SplFileObject::current() - Retrieve current line of file
SplFileObject::key() - Get line number
SplFileObject::seek() - Seek to specified line
SplFileObject::rewind() - Rewind the file to the first line
SplFileObject::valid() - Not at EOF

User Contributed Notes

quijote dot shin at gmail dot com 21-May-2017 09:03


As @Jonnycake  pointed there is no documentation about the following behavior of  next();



You need to call current() to really move forward without the need of a source loop.



Be:

<?php

$file = new SplFileObject("file.txt");



echo PHP_EOL . $file->current();

$file->next();

 $file->next();

 $file->next();

echo PHP_EOL . $file->current(); // 2nd line of the file



?>



<?php

$file = new SplFileObject("file.txt");



echo PHP_EOL . $file->current();

$file->next(); $file->current();

$file->next(); $file->current();

$file->next(); 

echo PHP_EOL . $file->current(); // be the 4th line of the file



?>



Honestly, I don't know if it is  waste of memory and/or CPU .

Jonnycake 02-Dec-2014 05:53


Quick note when using next(), it appears that you have to already be at the end of the line in order for it to hop to the next one.  I realized this while attempting to do a lineCount implementaiton like the following:



<?php

  function lineCount($file)

  {

     $x=0;

     while(!$file->eof()) {

          $x++;

          $file->next();

     }

     return $x;

  }

  $file=new SplFileObject("something");

  echo lineCount($file);

?>



It ended up in an infinite loop.  The solution was to just call fgets()/current() in the loop, although it wasn't being used anywhere so the following works:



<?php

  function lineCount($file)

  {

     $x=0;

     while(!$file->eof()) {

          $file->current();

          $x++;

          $file->next();

     }

     return $x;

  }

  $file=new SplFileObject("something");

  echo lineCount($file);

?>