`u`

The u filter wraps a text in a Unicode object (a Symfony UnicodeString instance <https://symfony.com/doc/current/components/string.html>_) that exposes methods to "manipulate" the string.

Let's see some common use cases.

Wrapping a text to a given number of characters:

.. code-block:: twig

{{ 'Symfony String + Twig = <3'|u.wordwrap(5) }}
Symfony
String
+
Twig
= <3

Here, u is the filter and wordwrap(5) is a method called on the result of the filter; it's equivalent to (text|u).wordwrap(5).

Truncating a string:

.. code-block:: twig

{{ 'Lorem ipsum'|u.truncate(8) }}
Lorem ip

{{ 'Lorem ipsum'|u.truncate(8, '...') }}
Lorem...

By default, truncate cuts text at the exact length. Pass false as the third argument to preserve whole words:

.. code-block:: twig

{{ 'Lorem ipsum dolor'|u.truncate(10, '...', false) }}
Lorem ipsum...

Converting a string to snake case or camelCase:

.. code-block:: twig

{{ 'SymfonyStringWithTwig'|u.snake }}
symfony_string_with_twig

{{ 'symfony_string with twig'|u.camel.title }}
SymfonyStringWithTwig

You can also chain methods:

.. code-block:: twig

{{ 'Symfony String + Twig = <3'|u.wordwrap(5).upper }}
SYMFONY
STRING
+
TWIG
= <3

.. note::

The ``u`` filter is part of the ``StringExtension`` which is not installed
by default. Install it first:

.. code-block:: bash

    $ composer require twig/string-extra

Then, on Symfony projects, install the ``twig/extra-bundle``:

.. code-block:: bash

    $ composer require twig/extra-bundle

Otherwise, add the extension explicitly on the Twig environment::

    use Twig\Extra\String\StringExtension;

    $twig = new \Twig\Environment(...);
    $twig->addExtension(new StringExtension());