Re: Length of a held expression
- To: mathgroup at smc.vnet.net
- Subject: [mg96546] Re: Length of a held expression
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Mon, 16 Feb 2009 06:56:24 -0500 (EST)
- References: <gn8jdj$7qa$1@smc.vnet.net>
Hi,
b = Sequence[1, 2];
Hold[{b, 3}] /. Hold[a_] :> Length[Unevaluated[a]]
??
Regards
Jens
Nikolaus Rath wrote:
> Hello,
>
> How can I get the length of a list in a Hold[] expression? I.e. if
>
> b = Sequence[1,2];
>
> then I want the length of {b,3} given as 2. But
>
> Length[{b,3}]
>
> gives me the length after splicing in b (which is 4), while
>
> Length[Hold[{b,3}]]
>
> gives me the length of the hold expression (which is 1).
>
>
> Anyone able to help?
>
>
> Best,
>
> -Nikolaus
>
> --
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