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