RE: Sequence and Or
- To: mathgroup at smc.vnet.net
- Subject: [mg34196] RE: [mg34179] Sequence and Or
- From: "DrBob" <majort at cox-internet.com>
- Date: Thu, 9 May 2002 05:15:57 -0400 (EDT)
- Reply-to: <drbob at bigfoot.com>
- Sender: owner-wri-mathgroup at wolfram.com
Thanks for the workaround! It makes me wonder, though, why Or should have the HoldAll attribute at all. Bobby -----Original Message----- From: Andrzej Kozlowski [mailto:andrzej at platon.c.u-tokyo.ac.jp] To: mathgroup at smc.vnet.net Subject: [mg34196] Re: [mg34179] Sequence and Or Compare: In[19]:= Or[Sequence@@{True,False,True}] Out[19]= Sequence[True,False,True] In[20]:= Or[Evaluate[Sequence@@{True,False,True}]] Out[20]= True In[21]:= Or[Sequence[True,False,True]] Out[21]= True The point is the HoldAll attribute of Or. Because of it, when you enter Or[Sequence@@{True,False,True}] only a single argument is passed to Or but Or with a single argument returns: In[22]:= Or[x] Out[22]= x Andrzej Kozlowski Toyama International University JAPAN http://platon.c.u-tokyo.ac.jp/andrzej/ On Wednesday, May 8, 2002, at 02:57 PM, DrBob wrote: > When I evaluate the following... > > {True,False,True} > Or@@% > Sequence@@% > Or[%] > > the outputs are: > > {True,False,True} > True > Sequence[True,False,True] > Sequence[True,False,True] > > while I had expected: > > {True,False,True} > True > Sequence[True,False,True] > True > > What am I missing? > > Bobby Treat > > > > >