Re: substitution rules and patterns
- To: mathgroup at smc.vnet.net
- Subject: [mg3417] Re: [mg3410] substitution rules and patterns
- From: jpk at apex.mpe.FTA-Berlin.de (Jens-Peer Kuska)
- Date: Wed, 6 Mar 1996 01:45:48 -0500
- Sender: owner-wri-mathgroup at wolfram.com
Hi Susan, Yes ..
>
> Could someone tell me why the first substitution rule
> works and the second doesn't----
>
> In[70]:= (c^2)^(d/2)/.{(a_^2)^(b_ /2)->a^b}
Here we have
Power[
Power[c,2],
Times[
d,
Power[2,-1]
]
]
as in Your Patten
>
> Out[70]= c^d
>
>
>
> In[71]:= (c^2)^(5/2)/.{(a_^2)^(b_ /2)->a^b}
Here we have
Power[
Power[c,2],
Rational[5,2]
]
as You see the two expressions are completly different, and
the pattern b_/2 will not match Rational[5,2].
If You are not shure with the pattern look allways to
the FullForm of Your expression.
Hope that helps
Jens
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