Re: Sequence and Or
- To: mathgroup at smc.vnet.net
- Subject: [mg34192] Re: [mg34179] Sequence and Or
- From: Andrzej Kozlowski <andrzej at platon.c.u-tokyo.ac.jp>
- Date: Thu, 9 May 2002 05:15:52 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
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
>
>
>
>
>