Re: Length of a held expression

• To: mathgroup at smc.vnet.net
• Subject: [mg96589] Re: Length of a held expression
• From: Nikolaus Rath <Nikolaus at rath.org>
• Date: Mon, 16 Feb 2009 16:41:20 -0500 (EST)
• References: <gn8jdj\$7qa\$1@smc.vnet.net> <gnbkf1\$3gn\$1@smc.vnet.net>

```Raffy <raffy at mac.com> writes:
> 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}]

Hmmm. Ingenious :-). Thanks a lot. Although for my application
Length[Unevaluated[a]] is more concise, I'm sure I'll be grateful for
your construct at some later point.

Best,

-Nikolaus

--
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```

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