Validates that all the elements of the given collection are unique (none of them

is present more than once). Elements are compared strictly, so ``'7'`` and ``7``

are considered different elements (a string and an integer, respectively).

is present more than once). By default elements are compared strictly,

so ``'7'`` and ``7`` are considered different elements (a string and an integer, respectively).

If you want any other comparison logic to be applied, use the `normalizer`_ option.

..seealso::

Applies to:ref:`property or method<validation-property-target>`

Options - `groups`_

- `message`_

- `normalizer`_

- `payload`_

Class:class:`Symfony\\Component\\Validator\\Constraints\\Unique`

Validator:class:`Symfony\\Component\\Validator\\Constraints\\UniqueValidator`

``{{ value }}`` The current (invalid) value

``normalizer``

**type**: a `PHP callable`_ **default**: ``null``

..versionadded::5.3

The ``normalizer`` option was introduced in Symfony 5.3.

This option allows to define the PHP callable applied to each element of the given collection before

checking if the collection is valid.

For example, you may want to pass the ``'trim'`` string to apply the

:phpfunction:`trim` PHP function to each element of the collection in order to ignore leading and trailing

whitespace during validation.

..include::/reference/constraints/_payload-option.rst.inc

.. _`PHP callable`:https://www.php.net/callable