Re: Seemingly strange behavior - HoldForm and Evaluate
- To: mathgroup at smc.vnet.net
- Subject: [mg68127] Re: Seemingly strange behavior - HoldForm and Evaluate
- From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
- Date: Tue, 25 Jul 2006 04:01:26 -0400 (EDT)
- Organization: Uni Leipzig
- References: <ea1nqf$pns$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, because Plus[] has no HoldAll attribute that can be removed .... and Evaluate[] does nothing if its not directly wrapped around a a argument of a function that does not evaluate this arguments. Regards Jens "Bharat Bhole" <bbhole at gmail.com> schrieb im Newsbeitrag news:ea1nqf$pns$1 at smc.vnet.net... |I came across this when answering one of the queries posted on this forum. | | If I write | | (1) | In: a = 2; | HoldForm[a] | | Out: a | | (2) | In: a=2; | HoldForm[Evaluate[a]] | | Out: 2 | | (3) In: a=2; | b=3; | HoldForm[Evaluate[a] + Evaluate[b]] | | Out: Evaluate[a] + Evaluate[b] | | | | Example 2 seems to suggest that Evaluate works as expected, i.e., it | evaluates the expression assigns value 2 despite the HoldAll attribute of | HoldForm. However, in example 3, evaluate does not function as expected, or | may it does, but I do not understand why a and b are not assigned there | values. | | Thanks, | Bharat. | |