SplFileObject::fgets

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

SplFileObject::fgets — Obtener la línea de el fichero

Descripción

public SplFileObject::fgets(): string

Obtener la línea de el fichero.

Parámetros

Esta función no tiene parámetros.

Valores devueltos

Devuelve un string conteniendo la siguiente línea de el fichero.

Errores/Excepciones

Lanza una RuntimeException si el fichero no puede ser leído.

Ejemplos

Ejemplo #1 Ejemplo de SplFileObject::fgets()

Este ejemplo simplemente imprime el contenido de texto.txt línea por línea.

<?php
$fichero = new SplFileObject("texto.txt");
while (!$fichero->eof()) {
    echo $fichero->fgets();
}
?>

Ver también

fgets() - Obtiene una línea desde el puntero a un fichero
SplFileObject::fgetss() - Obtiene la línea de el fichero y elimina etiquetas HTML
SplFileObject::fgetc() - Obtiene un caracter del fichero
SplFileObject::current() - Recupera la línea actual del fichero

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User Contributed Notes 3 notes

down

Lucas Bustamante ¶

3 years ago

Notice that the behavior of fgets after a seek changed on PHP 8.0.10, if you seek to line 50 and run fgets, it will give you line 50, while on PHP 5.1~8.0.0 it would give you line 51:

<?php

$file = new SplTempFileObject();

for ($i = 0; $i < 100; $i++) {
    $file->fwrite("Foo $i\n");
}

$file->seek(50);

echo json_encode(array(
    array('line' => $file->key(), 'contents' => trim($file->fgets())),
    array('line' => $file->key(), 'contents' => trim($file->fgets())),
    array('line' => $file->key(), 'contents' => trim($file->fgets())),
), JSON_PRETTY_PRINT);

?>

Results:

PHP  8.0.1+
[
    {
        "line": 50,
        "contents": "Foo 50"
    },
    {
        "line": 50,
        "contents": "Foo 51"
    },
    {
        "line": 51,
        "contents": "Foo 52"
    }
]

PHP 5.1 to 8.0.0
[
    {
        "line": 50,
        "contents": "Foo 51"
    },
    {
        "line": 51,
        "contents": "Foo 52"
    },
    {
        "line": 52,
        "contents": "Foo 53"
    }
]

down

Chris Johnson ¶

6 years ago

Note that this method will cause a PHP fatal error if the file being read contains no recognizable line termination characters and is larger than the allowable memory size for PHP to allocate, i.e. memory_limit set in php.ini or similar.  In other words, PHP keeps reading until it finds a line termination, if it runs out of memory first, it will throw a fatal error.

This is different from the file resource fread() function, which allows an optional maximum length argument to be passed to limit this behavior.

down

Lucas Bustamante ¶

3 years ago

I forgot to mention in my previous note about PHP PHP 8.0.10, that you can use $file->current(); $file->next(); as a replacement for $file->fgets(); that works consistently from PHP 5.1 to 8.0.1+ after a seek():

<?php

$file = new SplTempFileObject();

for ($i = 0; $i < 100; $i++) {
    $file->fwrite("Foo $i\n");
}

$file->seek(50);

print_r(array(
    array('line' => $file->key(), 'contents' => trim($file->current()), 'triggerNext' => $file->next()),
    array('line' => $file->key(), 'contents' => trim($file->current()), 'triggerNext' => $file->next()),
    array('line' => $file->key(), 'contents' => trim($file->current()), 'triggerNext' => $file->next()),
));

?>

PHP 5.1 to 8.0.1+:

[
    {
        "line": 50,
        "contents": "Foo 50"
    },
    {
        "line": 51,
        "contents": "Foo 51"
    },
    {
        "line": 52,
        "contents": "Foo 52"
    }
]

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