SplFileObject::key

(PHP 5 >= 5.1.0, PHP 7)

Get line number

public int SplFileObject::key ( void )

Gets the current line number.

Note:

This number may not reflect the actual line number in the file if SplFileObject::setMaxLineLen() is used to read fixed lengths of the file.

Returns:

Returns the current line number.

Examples:

SplFileObject::key() example

<?php
$file = new SplFileObject("lipsum.txt");
foreach ($file as $line) {
    echo $file->key() . ". " . $line;
}
?>

The above example will output something similar to:

0. Lorem ipsum dolor sit amet, consectetur adipiscing elit. 
1. Duis nec sapien felis, ac sodales nisl. 
2. Lorem ipsum dolor sit amet, consectetur adipiscing elit.

SplFileObject::key() example with SplFileObject::setMaxLineLen()

<?php
$file = new SplFileObject("lipsum.txt");
$file->setMaxLineLen(20);
foreach ($file as $line) {
    echo $file->key() . ". " . $line . "\n";
}
?>

The above example will output something similar to:

0. Lorem ipsum dolor s
1. it amet, consectetu
2. r adipiscing elit. 
3. 

4. Duis nec sapien fel
5. is, ac sodales nisl
6. . 

7. Lorem ipsum dolor s
8. it amet, consectetu
9. r adipiscing elit.