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Length of a held expression

• To: mathgroup at smc.vnet.net
• Subject: [mg96524] Length of a held expression
• From: Nikolaus Rath <Nikolaus at rath.org>
• Date: Sun, 15 Feb 2009 03:23:23 -0500 (EST)

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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• Follow-Ups:
  • Re: Length of a held expression
    • From: Leonid Shifrin <lshifr@gmail.com>
  • Re: Length of a held expression
    • From: Andrzej Kozlowski <akoz@mimuw.edu.pl>