What I thought was the first non-trivial example I'd found of PHP being shorter than Python. Saved by Twitter.

values.php

<?

/**
 * getValues(array('a' => 1, 'b' => 2), array('b', 'c')); # => array('b' => 2)
 */
function getValues($data, $fields)
{
    return array_intersect_key($data, array_flip($fields));
}

values.py

def values(data, fields):
    """
    >>> values({'a': 1, 'b': 2}, ['b', 'c'])
    {'b': 2}
    """
    return dict((k, data[k]) for k in fields if k in data)