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    <h3>Editing: ParameterBag.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Symfony\Component\HttpFoundation;

use Symfony\Component\HttpFoundation\Exception\BadRequestException;

/**
 * ParameterBag is a container for key/value pairs.
 *
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 *
 * @implements \IteratorAggregate&lt;string, mixed&gt;
 */
class ParameterBag implements \IteratorAggregate, \Countable
{
    /**
     * Parameter storage.
     */
    protected $parameters;

    public function __construct(array $parameters = [])
    {
        $this-&gt;parameters = $parameters;
    }

    /**
     * Returns the parameters.
     *
     * @param string|null $key The name of the parameter to return or null to get them all
     *
     * @return array
     */
    public function all(/* ?string $key = null */)
    {
        $key = \func_num_args() &gt; 0 ? func_get_arg(0) : null;

        if (null === $key) {
            return $this-&gt;parameters;
        }

        if (!\is_array($value = $this-&gt;parameters[$key] ?? [])) {
            throw new BadRequestException(sprintf('Unexpected value for parameter &quot;%s&quot;: expecting &quot;array&quot;, got &quot;%s&quot;.', $key, get_debug_type($value)));
        }

        return $value;
    }

    /**
     * Returns the parameter keys.
     *
     * @return array
     */
    public function keys()
    {
        return array_keys($this-&gt;parameters);
    }

    /**
     * Replaces the current parameters by a new set.
     */
    public function replace(array $parameters = [])
    {
        $this-&gt;parameters = $parameters;
    }

    /**
     * Adds parameters.
     */
    public function add(array $parameters = [])
    {
        $this-&gt;parameters = array_replace($this-&gt;parameters, $parameters);
    }

    /**
     * Returns a parameter by name.
     *
     * @param mixed $default The default value if the parameter key does not exist
     *
     * @return mixed
     */
    public function get(string $key, $default = null)
    {
        return \array_key_exists($key, $this-&gt;parameters) ? $this-&gt;parameters[$key] : $default;
    }

    /**
     * Sets a parameter by name.
     *
     * @param mixed $value The value
     */
    public function set(string $key, $value)
    {
        $this-&gt;parameters[$key] = $value;
    }

    /**
     * Returns true if the parameter is defined.
     *
     * @return bool
     */
    public function has(string $key)
    {
        return \array_key_exists($key, $this-&gt;parameters);
    }

    /**
     * Removes a parameter.
     */
    public function remove(string $key)
    {
        unset($this-&gt;parameters[$key]);
    }

    /**
     * Returns the alphabetic characters of the parameter value.
     *
     * @return string
     */
    public function getAlpha(string $key, string $default = '')
    {
        return preg_replace('/[^[:alpha:]]/', '', $this-&gt;get($key, $default));
    }

    /**
     * Returns the alphabetic characters and digits of the parameter value.
     *
     * @return string
     */
    public function getAlnum(string $key, string $default = '')
    {
        return preg_replace('/[^[:alnum:]]/', '', $this-&gt;get($key, $default));
    }

    /**
     * Returns the digits of the parameter value.
     *
     * @return string
     */
    public function getDigits(string $key, string $default = '')
    {
        // we need to remove - and + because they're allowed in the filter
        return str_replace(['-', '+'], '', $this-&gt;filter($key, $default, \FILTER_SANITIZE_NUMBER_INT));
    }

    /**
     * Returns the parameter value converted to integer.
     *
     * @return int
     */
    public function getInt(string $key, int $default = 0)
    {
        return (int) $this-&gt;get($key, $default);
    }

    /**
     * Returns the parameter value converted to boolean.
     *
     * @return bool
     */
    public function getBoolean(string $key, bool $default = false)
    {
        return $this-&gt;filter($key, $default, \FILTER_VALIDATE_BOOLEAN);
    }

    /**
     * Filter key.
     *
     * @param mixed $default Default = null
     * @param int   $filter  FILTER_* constant
     * @param mixed $options Filter options
     *
     * @see https://php.net/filter-var
     *
     * @return mixed
     */
    public function filter(string $key, $default = null, int $filter = \FILTER_DEFAULT, $options = [])
    {
        $value = $this-&gt;get($key, $default);

        // Always turn $options into an array - this allows filter_var option shortcuts.
        if (!\is_array($options) &amp;&amp; $options) {
            $options = ['flags' =&gt; $options];
        }

        // Add a convenience check for arrays.
        if (\is_array($value) &amp;&amp; !isset($options['flags'])) {
            $options['flags'] = \FILTER_REQUIRE_ARRAY;
        }

        if ((\FILTER_CALLBACK &amp; $filter) &amp;&amp; !(($options['options'] ?? null) instanceof \Closure)) {
            trigger_deprecation('symfony/http-foundation', '5.2', 'Not passing a Closure together with FILTER_CALLBACK to &quot;%s()&quot; is deprecated. Wrap your filter in a closure instead.', __METHOD__);
            // throw new \InvalidArgumentException(sprintf('A Closure must be passed to &quot;%s()&quot; when FILTER_CALLBACK is used, &quot;%s&quot; given.', __METHOD__, get_debug_type($options['options'] ?? null)));
        }

        return filter_var($value, $filter, $options);
    }

    /**
     * Returns an iterator for parameters.
     *
     * @return \ArrayIterator&lt;string, mixed&gt;
     */
    #[\ReturnTypeWillChange]
    public function getIterator()
    {
        return new \ArrayIterator($this-&gt;parameters);
    }

    /**
     * Returns the number of parameters.
     *
     * @return int
     */
    #[\ReturnTypeWillChange]
    public function count()
    {
        return \count($this-&gt;parameters);
    }
}
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