Performs a series of filters against variables in the specified
context and returns the results as an associative array. The context
is one of
options parameter is an associative array
where each element’s key is a variable name, with the associated value
defining the filter and options to use to filter that variable’s
value. The definition is either the ID of the filter to use or an
array containing one or more of the following elements:
The ID of the filter to apply.
A bitfield of flags.
An associative array of options specific to the filter.