SplFileObject::key

Get line number

&reftitle.description; public `int` `SplFileObject::key`

Gets the current line number.

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

&reftitle.parameters; &no.function.parameters;
&reftitle.returnvalues;

Returns the current line number.

&reftitle.examples;

### `SplFileObject::key` example

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

&example.outputs.similar;

    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";
    }
    ?>

&example.outputs.similar;

    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.

&reftitle.seealso;

- `SplFileObject::current`
- `SplFileObject::seek`
- `SplFileObject::next`
- `SplFileObject::rewind`
- `SplFileObject::valid`