Re: Filtering out mail without a "From" header

Liviu Daia suggested to Dominic Mitchell,

|       :0:
|       * ! ^From:
|       spam
| 
|       :0:
|       * ! ^(To|Cc):
|       spam
| 
|       :0:
|       * ! ^Received:
|       spam

Question for Philip and the other cognoscenti: how do those three recipes
compare for efficiency to this?

     :0
     * ^From:
     * ^(To|Cc):
     * ^Received:
     { }
     :0E:
     spam