Re: Length of a held expression
- To: mathgroup at smc.vnet.net
- Subject: [mg96564] Re: Length of a held expression
- From: Raffy <raffy at mac.com>
- Date: Mon, 16 Feb 2009 06:59:43 -0500 (EST)
- References: <gn8jdj$7qa$1@smc.vnet.net>
Remember, Hold[{b,3}] is really just Hold[List[b,3]].
And what you're looking for is something like: Length[Hold[b,3]].
So replace head List with Hold, and head Hold with Length.
Length @@ Hold @@@ Hold[{b,3}]