Remove a parameter from a query

when HTTP_REQUEST {
if { [HTTP::uri] contains "X-VODAFONE-3GPDPContext=" } {
HTTP::uri [string map {"X-VODAFONE-3GPDPContext=" ""} [HTTP::uri]]
}
}

when HTTP_REQUEST {

    Check if the query string parameter value isn't null
   if {[HTTP::query] contains "X-VODAFONE-3GPDPContext="}{

       Use a workaround to parse the parameter value from the query string
       described on http://devcentral.f5.com/wiki/default.aspx/iRules/uri__query
      set param_value [URI::query "?&[HTTP::query] "&X-VODAFONE-3GPDPContext"]

       Save a copy of the URI with the param and value removed
      set uri [string map [list "X-VODAFONE-3GPDPContext=$param_value" ""] [HTTP::uri]]

       Replace && with & in the updated query string if && is present and set the URI to this
      HTTP::uri [string map "&& &" $uri]

       Log the cached and updated values for the URI
      log local0. "Original URI: [HTTP::uri], updated URI: [string map "&& &" $uri]"
   
   }
}