Re: Nesting in patterns
- To: mathgroup at smc.vnet.net
- Subject: [mg8592] Re: [mg8565] Nesting in patterns
- From: David Withoff <withoff>
- Date: Sun, 7 Sep 1997 22:13:11 -0400
- Sender: owner-wri-mathgroup at wolfram.com
> Can I have nested blanks in patterns? Specifically,
> I would like to be able to do something like
>
> MatchQ[{{1,2},{1,2}}, {x__}__]
>
> with the x matching the sequence 1,2 . This doesn't work,
> but is there something similar that I can do?
>
> Will Self
> Montana State University Billings
> "The University of the Yellowstone Valley"
Will a pattern like this do what you want?
In[1]:= MatchQ[{{1,2},{1,2}}, {{x__}..}]
Out[1]= True
The expression {x__}__ evaluates to {__ x__}, a list containing
the product of __ and x__, which is probably not what you wanted.
Dave Withoff
Wolfram Research