Re: MatchQ, silly question
- To: mathgroup at smc.vnet.net
- Subject: [mg105130] Re: MatchQ, silly question
- From: janos <janostothmeister at gmail.com>
- Date: Sun, 22 Nov 2009 06:07:31 -0500 (EST)
- References: <he5v9i$3gh$1@smc.vnet.net> <he896k$q8g$1@smc.vnet.net>
An alternative solution from my student, Attila L=E1szl=F3 NAGY is: MatchQ[3 x^2, #] & /@ {3 x_^2, 3 x_^_, _ x_^_, _ _Symbol^_, _ (_Symbol^_), _*(_Symbol^_)} J=E1nos ************************************************************************** On nov. 21, 09:43, David Bailey <d... at removedbailey.co.uk> wrote: > janos wrote: > > MatchQ[3 x^2, #] & /@ {3 x_^2, 3 x_^_, _ x_^_, _ _^_, _ (_^_), _ * > > (_^_)} > > > dives False in the last cases. Why? The FullForm > > > Power[Blank[ ],Plus[1,Blank[ ]]] > > > contains Plus, why? > > > Thank you. > > > J=E1nos > > Because expressions still evaluate, even if they contain Blank[] - this > can be easily seen by entering the expression _+_ . > > Wrap the pattern in HoldPattern to prevent evaluation. > > David Baileyhttp://www.dbaileyconsultancy.co.uk