Re: trivial question
- To: mathgroup at smc.vnet.net
- Subject: [mg69819] Re: [mg69798] trivial question
- From: "Carl K. Woll" <carlw at wolfram.com>
- Date: Sat, 23 Sep 2006 23:45:22 -0400 (EDT)
- References: <200609230844.EAA22579@smc.vnet.net>
dimmechan at yahoo.com wrote: > Hi. > > I think this is rather trivial, but I can think something right now. > > Why the commands below result in different output? > > (HoldForm[+##1]&)@@list > 1+2+3 > > HoldForm[Plus]@@list > Plus[1,2,3] > > Thanks in advance. The first expression's FullForm is (assuming list={1,2,3}): HoldForm[Plus[1,2,3]] while the second expression is: HoldForm[Plus][1,2,3] In the first case HoldForm formats Plus[1,2,3] without evaluation to get 1+2+3. In the second case HoldForm formats Plus without evaluation to get Plus. However, there is no formatting rule (MakeBoxes) for the head HoldForm[Plus], so no further formatting occurs. Carl Woll Wolfram Research
- References:
- trivial question
- From: dimmechan@yahoo.com
- trivial question